Here's the answer:
The AP-270 numbers are quoted per chain to make it more consistent with the rest of the campus AP part numbers.
Therefore the numbers have to be adjusted by 4.8 dB downward to get to system sensitivity.
AP-175 was quoted as aggregate (included MRC benefit)
The AP-270 has integrated the Advanced cellular colocation filtering which has a net sensitivity impact of about 0.6 dB relative to Ap-175 where that function was provided external to the chassis.
AP-270 performance results show that it outperforms AP-175 at all ranges