The ecu will put in too much ignition timing if the maf reads low, as the maf is on of the 2 major load sensors for the engine. The other is the MAP.
If the ecu is seeing less load, it will add ignition timing. The knock sensors will pull some of it back out again, as you're now knocking.
I'd reset the battery, as I'd expect to see some retard in block 20. If you're getting none, you're not running at optimum timing, and therefore performance.
Unplugging the battery will reset tha adaption channels to 0 so you should see a little more timing.