Gonk, you're right as usual; I tried biwiring the Maggies from the Adcom's A and B terminals because I'd read somewhere that there might be a sonic benefit from having separate wires for tweeter and woofer feeds. (What other reason for biwiring would there be?) And the sound does seem to me to be marginally more detailed, especially in the treble.
Of course, as in so much of subjective judgment in audio, it could be autosuggestion.