Bi Amp Advice

For the last couple of years I have been using two PS Audio GCA 250's to vertically/passively bi-amp a pair of Quad 22L's.
I just did a test using one amp bi-wired. There was a pretty distinct difference. Mostly the highs and high mids were not as forward and the lows were not as punchy but just slightly. That being said the overall sound seemed a bit smoother and easier to listen to. Is it possible that there was a slight decrease in volume on the high end resulting in the perceived smoothness when bi-wiring as opposed to bi-amping? Depending on what you are looking for both set-ups sounding good.
Would I be better off purchasing a single amp like a Bryston 4B SST and bi wiring resulting in a happy medium between the two?