About 3 weeks ago my ltd mh400nt was setup by a tech for drop B tuning, I was jamming with friends and its justa fun chunky tuning to play in. Anyways today I went to switch back to drop c which is what I most commonly play in and I just cannot get it right. No matter what when I play an open note on the 5th string it buzzes horribly. It looks like the tech snaded the nut down too far. I went from 12-56 to 11-50. every other string sounds fine. Any suggestions?