Yeah client to the AP is 450 PHY.. But now next client you would have /2 of that automatically.. I can see how they can report PHY.. But come on – your wired interface is not even capable of half of your PHY your talking 1/4 of what your PHY is reported as so WTF would be the point???
Well you could get more if your client could do more than 1 stream.. Seems that is your limit.. You could in theory be seeing mid 90's with that AP but not if your client is only 1 stream..
3 streams at 20mhz with 800ns gi is 195 so do /2 of that to get you in real world your bottleneck would be the 10/100 interface on the device. But if your client only has 1 stream, low end laptop wifi, phones, etc.. very common to only have 1 stream.. What is your client in this testing??