Why is my inches/360 different with 5700 DPI vs 2850 DPI*2 sensitivity?

[dmbr]

When I set my in-game sensitivity (in Team Fortress 2) to 1.0 and my G9x's DPI to its maximum of 5700, I get about 3 inches per 360. When I halve my DPI to 2750 and double my in-game sensitivity to 2.0 to compensate, my inches/360 nearly doubles.

Shouldn't inches/360 = dpi*sensitivity? Why is this so dramatically not the case here?


I have all acceleration disabled and the game uses Raw Input.

[vun]

Well, the G9x sensor has some hardware acceleration, although so little it's barely worth mentioning.
I'm guessing the problem here lies in how the source engine scales sensitivity.

[daerid]

The only explanation I can think of is that the sensitivity setting isn't a linear scale.

[dmbr]

Oops, I was using a different dpi than I thought.

The inconsistency is still there now, but subtle.