Allright, I haven't been able to monkey with things until now but here are my findings.

I re-calibrated again with the DVE disc and things seem to have gotten progressively worse. Main reference level was set at -02db on the left main! All other levels needed to drop a bit more (close to -15 on all). Switching line level cable between amp & pre/pro did nothing. Speaker cable switch = nothing.

I put the right main on the other amp (the left speaker cable wouldn't reach) and, go figure, +4db or so on the rat shack meter!

Is there a condition that can slowly degrade a power amp signal? I find it hard to believe a digital signal would slowly degrade over time, ruling out the pre/pro (I think - not being an expert).

I am truly desperate to solve this problem as I am about to pull the trigger on a new set of mains (B&W 604s3) and would like to fed them what they want.....which is probably not a bunk signal

Again, any help is greatly (and desperatley needed).