Oh, so THAT'S why I can never find that checkbox! I'm sure my problem isn't with Gimp... I know about the special save format, to send the texture back to DXT Bmp I export it as a .bmp. When I click "refresh after edit" I can see the changes I made, which wouldn't happen if it were in .xcf format... dxtbmp wouldn't be able to use it at all. Same thing happens with the Abacus package, the xcf format won't show up on it, bmp does no problem.
What I meant by saving and not changing anything in the box... that's when I'm looking at dxtbmp, with my changes showing. Here, this is the first repaint I really consider finished, I've got a few others that still need something but I can't decide what. This was done with the combination of Abacus and Gimp.