I've encountered it before too, it's kinda random. What you should do is keep the lead and distortion tones' volumes separate. If for example Lead is -29dB, you dont have to have the Distortion at -29dB too. Experiment a bit, it's kind of a hit-or-miss deal, I can never get it right the first time. If your Lead is too loud, lower it by about 2db or something similar and raise the Distortion one by about 2db as well. Another thing to keep in mind is your song file's has it's own volume too in the RST, maybe your tones have the right volume but the .ogg is too loud, mess around with that too! Hope this helps!