Comment by phibz
It reads like he is assuming that missing messages from the mouse is not allowable.
I would say think of it this way: what happens when the mouse moves between USB hid messages?
If the mouse moves between messages sent via USB HID do the later messages capture the delta between the last and current message. Including the movement that happened in between?
Do the input messages, both those sent over USB by the mouse as well processed and presented by Windows, give relative or absolute positions?
The messages already represent a discrete sampling if a signal. You should be able to recreate the original information reasonably well without processing every single message.
Standard USB HID Mouse reports relative position change to previous report, so the reported position is difference from last polled one.