Can you guys help me find the ign. timing tables that are causing this behavior?

Can you guys explain why the timing steps down and up at the end of these two logs? I'm starting to dig into a jerking/bucking with the TCC locked up during a coast. I'm not sure if this timing issue is part of the cause but I would like to know why it's happening and probably smooth it out. I've dug around some but haven't stumble on to why it's happening. There seems to be several/ a lot of timing tables that may affect this. It almost looks like it's trying to make it idle when coasting below 1600 rpm or so. The same timing scenario shows up when the cruise is on, but I don't feel it in the drivers seat.
At the end of both of these logs is the example of the issue and my tune is also attached. The engine is a LS1, stroked to 383, heads, cam, and boosted, now on corn fuel. The problem was there before the fuel change and by the seat of the pants it slightly less noticeable with the new fuel. Again, thank you for your time and help.
Attachment 149473
Attachment 149474
Attachment 149475

Had the same issues with my car, with the performance cam you lose alot of low end torque, i had to raise my TCC lockup speeds to keep it from locking and lugging the engine down at lower RPMs where the engine isn't making a lot of torque, at least i think this was the correct solution, it worked for me, no more bucking while coasting at slower speeds

I agree with your thought process twenglish1 as I have tested that theory early on but I'm looking for why the ignition timing is doing what it is doing and is it a problem I should solve or leave it be as is?

I spent alot of time looking at the logs and tune file, the log that says check timing at the end, what were you seeing? It doesn't seem to be doing anything unusual, and the other log are you talking about the spark advance dropping down to 16 degrees at the end of the one log? I'm not sure why it would be doing this, maybe someone else might have some more input

Id try turning off the Spark smoothing or the AC Bump spark, and see what happens.

Do you have your In Gear Spark table much different than your Hi octane table?
If you have 20* in a cell in your IN Gear spark table and its being used on decel then you get to a certain point where it goes back to your Hi Octane table where is say 40* that amount of spark timing can be felt in your seat.

Or it could be DFCO or something like that. Or AC.
If you log all your spark channels it will show you where its being read from.

I found where the timing retard is coming from, Idle adaptive spark control, Idle overspeed vs rpm (ECM 12644) table. Now my question is, what are the variables that tell the PCM when to control the idle? Why does it attempt to bring it down to the not moving in neutral idle target when I'm coasting at say 1300 rpm in D4?