On a single mouse scroll the delta varies from screen to screen which is expected.

The DeltaMode is 0 which means the delta in the event is in pixels.

Problem is that on different screens the delta given by these events are not proportionate.

On a screen 1080px height, I get a deltaY of 4 on a single mouse scroll. and on a screen of 1600px height, I get a deltaY of 8 on a single mouse scroll.

The Scroll is not proportionate to the user screen and not affected by the current window height/width.