1. Sorry, I don't have enough time (for months!) to perform research by myself. Just have time to respond emails and do quick fixes - even right now I'm working ... My day is - working, family, working, family, working, sleeping, repeat ... Sometimes sleeping a few times a day - 4+2+1 hours
2. XBox360 textures has some size alignments. It is AMD hardware-related (as well as "texture tiling" called by some people as "swizzling"). My Untile code was based on GetTiledOffset() function borrowed from XDK, however everything else was written by me just by experimenting. I have no idea how small textures works there, perhaps this is some "special case". Sorry for that. (as far as I know, nobody else has reversed XBox360 texture formats, so there's no other references to look at).
P.S. Thank you for understanding and working on this. You are helping me to make UModel better