You don't state where you are seeing this on project-gc, but I assume this is from the BadgeGen tab on profile stats. If you're seeing it elsewhere, it may help to specify.
Anyway, my count between project-gc and geocaching is off as well, and in two different ways.
Geocaching: 564 travel bugs* + 1126 geocoins = 1690 total
Project-gc: 552 travel bugs + 1083 geocoins = 1635 total
* The discrepancy in the subtotal is due to how BadgeGen combines different types of travel bugs in the count, but even this count is different from what it should be. Per geocaching, I should have:
Travel bugs: 512
[2004 yellow] Jeep 4x4 travel bugs: 6
2005 white Jeep travel bugs: 6
2006 green Jeep travel bugs: 6
2007 red Jeep travel bugs: 7
Unite for Diabetes travel bugs: 27