The difference between your meter readings and the scan tool readings is still 0.1 volt, so I wouldn't say it's either the PCM or the MAF. I'd just say you had a difference in readings. Could be the calibration, could be wire resistive loss, could be multiple things.
You really need to monitor the MAF performance over multiple engine speeds as well as how quickly it responds to blips of the throttle and letting off the throttle to make sure it doesn't jump around or behave completely non-linearly. Then if you find a spot where it misbehaves, use your multimeter and back probe the sensor to confirm the behavior noted on the scan tool can also be noted with the multimeter.
-Rod