Filetype prioritised over track number - a bug?

I have a couple of albums where some tracks are ogg and some are mp3. I have used EasyTag to give them an album name and track number. However, the fuze insists on ignoring the track number on these albums and plays the mp3s first. I know I can convert from one format to another. However both these are lossy formats, and I would end up with a file with both mp3 AND ogg distortion combined, and it would be better if the firmware in the Fuze would simply prioritise the track number over the file type.

Meantime I can do a playlist, I know. But any chance of this?