I have one of the cheap ones too, in fact I have had that one for 2 years now without a single problem. I even ran 4-cell 19t with it and not a single problem.
Did you contact Mtroniks and let them know of this problem? I would bet they would have taken care of you very nicely, in fact I gurantee it
but if the low end one couldn't handle 4 cells I'd be leary of any Mtroniks product.
I just don't see how this makes any sense? Thats like saying that if a cavalier isn't fast niether is the corvette