2010 Camaro 3.6 Weird Ignition Issue and Possibly Maxed MAF?

Looking for some input on problem areas on this tune.
This car is a 2010 Camaro 3.6 LLT with the E69 ECU. It is twin turbocharged running approximately 7psi of boost. Currently running the stock LLT MAF in a blow through configuration in a 3" pipe (between intercooler and throttle body). It has upgraded return style boost referenced low side fuel system feeding stock high pressure fuel system.

I have a few areas of concern. Screenshot here.
Attachment 121321
First) Is this what the MAF looks like maxed? Just flatlines at approximately 12,000hz?
Second) Is the air load % dropping like it does because of the MAF maxing?
Third) What is causing the weird ignition timing between 2000 to 5000 rpms while at WOT?

Tune file and log attached here.
Attachment 121322
Attachment 121323

To update on this one, we installed a LFX MAF sensor into a 3.5" MAF straighten tube. The MAF no longer just plateaus around 12,000 Hz and am able to control fueling at WOT (as before, I tried increasing fueling via the MAF table in the lean areas with the stock LLT MAF and it wouldn't richen up anymore) I am still getting the fueling dialed in on this log, so fueling is not perfect by any means. But the ignition timing issue is still happening and I am not sure what is causing it.
Also, I am honestly unsure if the Air Load % looks normal. For it to come up very quick, peak and then taper off turns redline. If I do remember correctly from the dyno reading that peak air load % was at peak torque output. Boost is pretty quick on this car, it comes in quick to 4-5psi and then is about full 7psi by 5000 rpms and hold all the way out to redline. Thinking about adding a MAP sensor and adding to my MPVI2 Pro Link just so I can log boost pressure.

The ignition timing oscillation is very noticeable in the feel of the car and the dyno graph.

(screenshot of ignition timing oscillation)
Attachment 122011

(tune file and log attached)
Attachment 122012
Attachment 122013

To update this.
Was able to get the fueling all dialed in with the upgrade LFX MAF in the 3.5" MAF straightener tube.
I ended up taking the car off of the dyno and did a pull on the street and did not have the ignition timing oscillation happen. Without the weird ignition timing oscillation now the air load % looks pretty normal.

Now to fix a few issues on the car and then turn the boost up to make more power.

How do you upgrade the maf? I'm having the same issue with tuning issues with fueling around 5krpm