No confusion here. They are equivalent in the sense they are both Class B's and max power, the only thing KNBR-FM has a disadvantage would be the
Mid Peninsula where there's is significant shadowing. This would explain the drive from SSF to Sunnyvale showing KGMZ stronger than the other.
KNBR-FM L-R
RabbitEars.Info
KGMZ L-R
RabbitEars.Info
KGMZ has a slightly stronger signal in SJ, probably due to San Bruno Mtn being a few miles closer.
KGMZ doesn't have a 50KW AM to aid it in the difficult spots.