Was checking the code trying to understand how both the vanilla and your formula works in game and stubbled on the weight of platform foundation tiles.
It was written in code as 250, while i believe it is 200 in game? (assuming we are talking with kg)

By the way, I’d really appreciate it if you could help me understand how the acceleration expression works in game! I tried to find acceleration zero point for a 1275MN, 480t, 22 wide platform (using newton and gram) but got a top speed of 271 instead (unit not sure, assume is km/s, should be 485-495km/s in game depends on gravity direction)

You are quite right! I wonder if this value changed in the base game.

There is not enough data publicly available to know exactly what units are being used by the game. One could figure this out by experimentation. This does not affect the correctness of this mod, which uses dimensional analysis.