And I'll just add something to that.
If you saw Howdy's after fire pics you'd see that the chips had been stacked, with the bottom ones (with most weight on them) being the most mis-shapen. I had a couple once that were virtually square.
Those that were in boxes suffered more if the barrels were tightly packed. They got extra heat from the card burning which is what stuck them together in stacks or partial stacks.