People I know always say shit like that about the lip syncing, the reason it sounds like that on some songs as Tech has said, is they couldnt get the instrumentals or whatever from Don Juan, so hes forced to rap over the actual Track from the Anghellic CD or whatever CD it may be.
If you notice its only on the old ass songs he still does that you can hear the Vocals in the background, at least in my opinion. And the fact he has a DJ now helps too.