[Dave at Pelican Parts]

I believe you are correct in the "why". It's pretty big liability if they get it wrong, so to be safe they just replace the pan.

I do not have direct experience with the Time-Sert for something as thin as an oil drain, but I would be surprised if it would not work. There may be some issue with the thickness of the Time-Sert and/or the space available for installation, so double check all of the measurements you can. (E.g., is there enough meat around the drain hole to properly hold the time-sert, is there a straight enough shot to properly do the prep and to properly get it in place, is there anything on the inside of the pan that might foul on the Time-Sert, etc.)

--DD