I've seen you mention this before. Do you have documentation this is the case, because I have never seen anything about the AE having any kind of QOS?
It is not stated in any of the Apple documentation. You can verify that there is a QoS function running if you were to pull packets using a tool like Wireshark. Furthermore, without QoS, the AirPort would fall flat on its face and be the performance equivalent of a turtle if you fired up say 5 streaming videos with a VoIP call going, but it does not and actually handles perfectly fine in most cases. Personally, I would prefer a user configurable QoS similar in setup to that offered by Netgear and ASUS routers.