My reciever is only one model year out of date, so maybe I'll see if there are any firmware updates for it.
I really don't think it would make a significant difference overall with the final result as I have always adjusted the subwoofer volume to a point that Audyssey can handle it. What I've found is that if the subwoofer volume is up too loud the Audyssey cannot lower the volume enough and it ends up with a bass hump. Since we're using identical subwoofers I was able to confirm that I have mine set at approximately the same level already.
I really don't think it would make a significant difference overall with the final result as I have always adjusted the subwoofer volume to a point that Audyssey can handle it. What I've found is that if the subwoofer volume is up too loud the Audyssey cannot lower the volume enough and it ends up with a bass hump. Since we're using identical subwoofers I was able to confirm that I have mine set at approximately the same level already.