Xelasoft MOD-edit does not support Moonsound... I think Moonsound was created later. Other than that it is quite a nice program and gets the job done... I've created only one MOD with it though... IIRC only music extension it supports is MSX-Audio (to enable stereo effect) NOP has made a nice MOD-player for Moonsound though.
Yes, Xelasoft mod-edit supports needs a turbo R to run and an MSX-Audio (with sampleram) to be used as intended.
Moonsoft also made a modplayer for Moonsound by the way.