Thanks for the suggestion, probably that was the case but it wasn't so bad for my intended usage, the reason I asked was more because I want to understand what I'm doing than fixing the macro; if the move mouse action values are in pixel that didn't seems what I was getting. Anyway I ended up putting a 0.01 pause (one tenth of what you suggested) and it seems like a good compromise. Also consider that, in the software I mentioned, if you press the shift key while dragging you get a finer resolution, and this works also with your Macro.
Thanks a lot again, you saved my day! (and possibly my wrist)