You do know that Thompson will replace a barrel or frame if you wear it out or stretch the frame with hot loads. I wouldn't want to put money on it, but my bet would be on Thompson helping you out.
I have seen many stretched frames replaced and one barrel that was totally worn out. it was a 10" and upon request for a 14" instead, they replaced it with the 14" with a no questions asked.
I wrote them a letter explaining everything. I would write a letter to Thompson with your true story and not try to BS them. That seems to work with most gun manufacturers.
I have another story. I bought a used 444 Marlin Texas in 1985. I really like the gun, but it didn't go over well with most Marlin people. It had a 24" round barrel, a half magazine and a Monte Carlo hump on the stock. It is still to this date my most accurate rifle in my battery at 100 yards.
I literally wore out the throat. Our local gunsmith didn't want to tackle a barrel replacement on it.
I called Marlin and talked to a very nice lady and explained my problem. She says that they will replace my barrel for $150. I sent it to them so fast it left a vapor trail behind it.
About 10 days later, the gunsmith called me and advised that the new barrel would be 22", as they don't make my barrel anymore, with Ballard 6 groove rifling and a 1 in 20" twist. However, he would have to replace the fore end and cap and the magazine tube. Did I want the fore end checkered or plain. Did I want my old parts? I did. The old fore end had hand checkering that matched the checkering on the butt stock. I wasn't ready to turn loose of it yet. (My old barrel was a 1 in 38" twist and I really wanted a faster twist.)
I was near panic when I asked how much that was going to cost. He says "Well, I showed this rifle to my foreman and he said charge him $75.00 plus shipping.
My total cost was $85.00 including shipping for the gun and another box for my old parts.
I told them in my letter of instructions that I had fired 3,374 rounds through it with fast burning powder and cast bullets and that is probably eroded the throat. They didn't care since i wore it out from use and not abuse. I think it pays to be honest with them and they will treat you well.
I wish you the best of luck.
Harold Clark