Yes, that's because the .lev files are from the OEM version. I specifically said you could move the Shareware levels into TSF, because (afaik) there is no OEM shareware, so I felt safe doing so.

Compression... basically, .lev files and .j2l files are very similar, but .j2l files are much more compressed. If you could replicate the process that turns .lev files into .j2l files, then you'd be fine, but I sincerely doubt you can do that.