Son,
For starters, the IRP (conducted power) is going to vary based on the transmitted modulation type/value used. But if we simply choose the greatest value for each band (2.4/5GHz) then it's 19dBm and 20dBm per MIMO chain, respectively.
With that said, the maximum conducted power will also vary based on the number of radio chains used.
For a
2SS transmission, add an additional
3dB
For a
3SS transmission, add an additional
4.8dB
For a
4SS transmission, add an additional
6dB
So if you configured the radio power for 15dBm and the transmission used 2 spatial streams, you would have an effective IRP of 18dBm. (before the antennas)
So to more precisely answer your question, the max conducted powers would be:
2.4GHz: 19dBm + 6dB (4SS) = 25dBm
5GHz: 20dBm + 6dB (4SS) = 26dBm
And just in case it's not already understood, these are IRP values, not EIRP. As such, you would then add any additional antenna gain onto these conducted power (IRP) values, which would then give you your final aggregate EIRP (which is what you ultimately care about when dealing with your local RF regulatory restrictions)