Hi Michael,
Sorry for the delay getting back on the QoS issue.
These settings are used by an SM if no other setting is available as the 'authenication server'
some more details are in this thread
An individual SM can never get more than 310Mbps total (even in 40MHz 5ms) so that is where that number is from.
It may have been better if this was automatically adjusted to reflect the DL percentage in the radio page settings. On 40MHz it is not unreasonable to go over 155Mbps DL to an individual SM (even at 64QAM) so yes well spotted that this needed changing too !
So in summary it's an setting used on a per SM basis (if no other QoS server setting is found) not throughput at the AP that is being set here and it should reflect the DL percentage. Link Test to a single SM will give you the theoretical max throughput in each direction for 6X and 8X performance.
Do you have some users with 'unlimited' packages on the sector doing speed tests ? :)
Hope that makes sense. Not a part of the user guide I had ever read before !
best regards,
Andy.