I would like to calculate the price of a BEP20 token in BNB. I checked poocoin and pancakeswap how they calculate the price. As I see they call continously the bsc-dataseed through web3.js, but I didn't find the solution yet.

The current status of my investigation:

1. they calling continously the dataseed (webrpc) to get the latest blocknumber:

// Request params
{
    "jsonrp": "2.0",
    "method": "eth_blockNumber",
    "params": [],
    "id": 1
}

2. After they received the latest block they immediately start another call with the following parameters

{
  "jsonrpc": "2.0",
  "id": 53,
  "method": "eth_call",
  "params": [
    {
      "to": "0x1ee38d535d541c55c9dae27b12edf090c608e6fb",
      "data": "0x252dba420000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000001c00000000000000000000000000000000000000000000000000000000000003800000000000000000000000000000000000000000000000000000000000000400000000000000000000000000000000000000000000000000000000000000048000000000000000000000000000000000000000000000000000000000000005000000000000000000000000000000000000000000000000000000000000000580000000000000000000000000000000000000000000000000000000000000060000000000000000000000000000000000000000000000000000000000000006800000000000000000000000000000000000000000000000000000000000000700000000000000000000000000000000000000000000000000000000000000078000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000000000000000880000000000000000000000000000000000000000000000000000000000000090000000000000000000000000000000000000000000000000000000000000009800000000000000000000000000000000000000000000000000000000000000a000000000000000000000000000000000000000000000000000000000000000a800000000000000000000000000000000000000000000000000000000000000b000000000000000000000000000000000000000000000000000000000000000b800000000000000000000000000000000000000000000000000000000000000c000000000000000000000000000000000000000000000000000000000000000c800000000000000000000000000000000000000000000000000000000000000d000000000000000000000000000000000000000000000000000000000000000d800000000000000000000000000000000000000000000000000000000000000e000000000000000000000000000000000000000000000000000000000000000e800000000000000000000000000000000000000000000000000000000000000f000000000000000000000000000000000000000000000000000000000000000f8000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000001080000000000000000000000000000000000000000000000000000000000000110000000000000000000000000003ff6c83226cdb10c7a42a2c54c67d63a135ab69000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000003fc20bdafdac6b2ae8f7f5f885f0819c2b968f0000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000008b018585d4949ae4714f057b66b8b033408bfa6000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000012c8db147721ac1e3e54e9ff73d99ef0ee4b1725000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000001b96b92314c44b159149f7e0303511fb2fc4774f000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000020bcc3b8a0091ddac2d0bc30f68e6cbb97de59cd000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000002c5d712cf39eaebc1ef2d1281eb48a70dcd34d49000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000003ab77e40340ab084c3e23be8e5a6f7afed9d41dc000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000003b872e6b1633f060680cf9c277b43dd1e254e564000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000056c77d59e82f33c712f919d09fceddf49660a829000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000006f656513f6e8eae19b6dc30cd372dd6ba4b5543a000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000070d8929d04b60af4fb9b58713ebcf18765ade422000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000007246d6ea86d34af343f03cc1eb952a4f98467a4e000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000007380e10f5c5f9dff4857de3cf9c39bb16f4c6dcf000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000007561eee90e24f3b348e1087a005f78b4c8453524000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000088c4bcf826410a81b58bc9b79a17641b443dc52e000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac0000000000000000000000000000000000000000000000000000000000000000000000000000000092ee07c591c26775b4d31259d5417e00553e857c000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac000000000000000000000000000000000000000000000000000000000000000000000000000000009adc6fb78cefa07e13e9294f150c1e8c1dd566c0000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000000000000000000000000000cc6b11de64dce6e5052a84b67cbbfd210ed530f7000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000000000000000000000000000d1f12370b2ba1c79838337648f820a87edf5e1e6000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000000000000000000000000000b3c4217ab2b265bf8c69718d280e3708b5e50577000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000000000000000000000000000b8875e207ee8096a929d543c9981c9586992eacb000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000000000000000000000000000c15fa3e22c912a276550f3e5fe3b0deb87b55acd000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000000000000000000000000000cee09ae86a78ce0cea3a4ea8cced5d41c0468e67000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000000000000000000000000000d9a0d1f5e02de2403f68bb71a15f8847a854b494000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000000000000000000000000000e7cc44de50b54906a9c1c48240650be2766481fc000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000000000000000000000000000fb7deb2236815222113d949d935cca4901531677000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000000000000000000000000000fa3107bca2ff6db4131bcd62b598cb00d9087f58000000000000000000000000000000000000000000000000000000000000004000000000000000000000000000000000000000000000000000000000000000040902f1ac00000000000000000000000000000000000000000000000000000000"
    },
    "latest"
  ]
}

As far as I know the 0x1ee38d535d541c55c9dae27b12edf090c608e6fb is a contract which contains the the multicall method. The first 10 characters of the data (0x252dba42) is the aggregate method. But what is the remaining part of the data?
This is the Contract ABI for aggregate method:

{
    "constant": true,
    "inputs": [
      {
        "components": [
            {"name": "target","type": "address"},
            {"name": "callData","type": "bytes"}
        ],
        "name": "calls",
        "type": "tuple[]"
      }
    ],
    "name": "aggregate",
    "outputs": [
      {
        "name": "blockNumber",
        "type": "uint256"
      },
      {
        "name": "returnData",
        "type": "bytes[]"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  }

The questions:

Is the 2nd call needed?
How can I calculate the price from those data?
Do you know an easier way?