Help me understand why LTFT jumps un & down

[LS XJ]

Thanks for reading

I've been into automotive over 45 years and feel comfortable with fuel injection, but tuning a PCM is new to me.
I'm wanting to get my 6.0 swap "safe" to drive, but my LTFT is way high. The truck drives smooth and strong, no issues driving.
I did 2 easy "around the block" drives and logged them, files attached. One with the MAF unplugged to see how it would affect the LTFT, and one with the MAF plugged in.

Question 1
What I'm wondering is WHY does the LTFT jump up and down greatly while the STFT is relatively low. The LTFT will be around +4 then a second later it's 25, what's with that? I thought LTFT was an average of STFT over a long period. Why if the STFT is reading single digits does the LTFT suddenly jump way up.

Driving with the MAF unplugged, the idle is slightly rougher, the throttle response is not as smooth, and the shifting is harsh ( I suspect the transmission needs airflow data to adjust shifting).

Question 2
How, or possible, do I reset the LTFT. If say, I've got a poor VE and the LTFT is very high, and I improve the VE, does the LTFT reflect that change immediately? If not, how then can I know that the trim is good, just view the STFT and ignore the LTFT and hope it comes down?

Thanks for you comments.

[LS XJ]

An update

In the above log I had logged the tuned file as posted. In this log I have zeroed out the MAF frequency as I saw on a video for tuning. I disabled the TM, not that I believe that I would encounter driving today that would activate TM.

It drove better, transmission still shifted a bit rough.

The STFT looks pretty good throughout both drives. The LTFT looks pretty good, but it would still occasionally jump to 11.
The "easy driving" log was the first drive.
An odd thing happened on the 2nd drive, "hill". This is a fairly steep hill, but the truck is so light and with 4.10 gears goes right up without much throttle. Now, at the top of the hill I pulled over to end the scan and save the file. It was idling fine when I stopped, but seconds after I clicked save it began to idle rough and had not much for throttle response, it then stalled and on a restart attempt it fired and died. Then no start. I "wrote" my previous tune to the PCM and it fired up and drove great.

I don't know why it ran good for the 20 minutes or so, and then died??

EDIT: The above preparation I read online. It said that the LTFT doesn't update immediately. It says to drive about 100 miles and at least 50 minutes. Well, when I zeroed the MAF, it DID run for about 20 minutes, then stalled. I tried the tuned file again and it won't even start. So I can't drive it to update the LTFT. Any suggestions?

Thanks for your help.