Autoboy, I have the NAD T785HD it is similar to the T765. The T785 does have Audyssey Dynamic Volume in light, medium and heavy flavors you can try these to see if there is an improvement. The NADs also have the "on the fly" temporary adjustments for the surrounds, center and sub on the remote (+-6dB).
I really can't add much to what others here have suggested but If Audyssey was used for calibration check that the distance is correct also make sure the polarity is correct. One more idea My Oppo 83SE has a Dynamic Compression in its setup that I make sure is turned off. I don't know what he uses for a transport but you may give that a look see although that should not affect just the center channel. As others here have stated I have not had that problem with the VP180 in my setup in fact it has been a great improvement over the VP150.
