I had exactly the opposite happen to me. (Actually a trans we "had" rebuilt for my son)
We took a 727 in for a bench rebuild. We had pulled the pan to drain upon removal of trans, and only put the pan back on by 4-5 bolts. 5/16-18 like all 727s from day 1.
We got it back with whatever scrounged up bolts the trans shop could dig up, the SOBs put M8s in it!!!! I had the same helicoil mess as you describe as a result.
I haven't been back since, went back to doing my own. Cheaper and I know it's done right.
I have a 12 ram 1500 with a 65 RFE trans (whatever RFE stands for,) and am about to do the 1st trans service since I bought it. Records show it had one done at 50k and I'm at 106k, (I missed doing one like I planned at 100kk I hope your thread isn't "advance warning of what I have took forward to.
I bought the filters from the stealership because the parts store couldn't decide if what they had would fit my truck or not. I wasn't expecting to pay around $80 for them!!!!! Damn.... That would buy me about 8 of them for a 727,904 or 46re.... And the price of ATF+4 has gotten ridiculous as well .. I never thought I'd see $11/quart at Walmart even.... Same as Napa wants.