I can't confirm anything, but in my opinion, I think you're getting pretty decent throughput on those. It's wireless - you're not going to get 54mb/s, even if that's what they advertise. Also, with wireless, usually the more bandwidth you're trying to get out of the WAP (i.e. 1mb vs 11mb vs 54mb vs 100mb, etc) the more the signal is succeptable to interference, and basically just plain doesn't work as well over longer distances or through barriers. You might even want to think about lowering them back to .b spec 11mb/s or lower.
