Widget size does not fit actual size during simulation

[1nsaneEExituuuU]

Hey i have this widget

it is 300x450 in size.
we have buttons in 4x7 grid.
our button is 75x62.2

When i take my mouse position on viewport during simulation i can see that a button from this grid is approx this size:
x=1419-1357=62
y=681-628=53

what am i missing here? It is messing up my calcs since i based it off widget size

[1nsaneEExituuuU]

using absolute size gives me the correct values for calculating around my widgets when they adapt to viewport.