Ive never tried to understand it that far in depth.
I started out with mine (Turbo 5.3) trying to tune it with the MAF and maxed it out and AFR went dumb. So learned how to tune it with COS3 on EFI Live and Speed Density, never looked back. Later on i swapped in a LQ4/80E with bigger 75mm turbo, retuned with larger injectors and W/M. Towed trailers heavier than the truck was rated for thru Texas, Louisiana, Mississippi, Alabama, Tennessee, and Kentucky. Never had a issue with AFR with weather or altitude changes. BUT, i was using Windshield Washer Fluid thru the Water/Meth injection system. I tuned it without W/M and then kinda tuned it with W/M but not rely on it in case of a failure. It stayed in constant boost (6-8psi) for a long time on some of those trips thru the hills of north Alabama towing 8500#. I put almost 300,000 miles on that setup with the turbo and only tweaked stuff such as Spark in the IAT table for the Methanol and shift points. Once i got the fuel dialed in and adjusted it a little for the W/M i let it be. Towed like a dream and turbo whistle got old after ahwile but oh well.
All i know is after tuning 12 Turbo charged and 2 supercharged LSx with a LS1B PCM's, MAF always gave me fits. COS3 or COS5 Speed Density was easy and worked great. There are IAT and ECT corrections for fuel in there. Also turning off the engine while fueling up let the PCM take a Baro reading before starting so it slightly adjusted for Altitude changes.