Woofers Gone Wild

Rega P3 with 301 arm/Sumiko BPS III. Even at lower levels, woofers in my B&W 803's are going nuts, flopping around all over the place (and I would imagine, sucking up lots of juice in the process).

Is there compliance mismatch here? From what I can tell, all should be well within the desired range. But still the woofer action.

TT is equipped with Black Diamond Racing footings, and is well placed. All adjustments on table checked/rechecked.

Am going to have a beer and not think about it for a while. Any others with this situation, or any solutions out there?

Thanks for any help,

Doc