Re: What do you tell the dealer
They won't care, and don't delete history. They will replace the DOC catalyst if needed. If you deleted the code, they will have an "out".
FCA wants a reflash done as step 1, which I'm sure changes some settings to hopefully correct P20EE, obviously doesn't. They want this step attempted first because this oxidation catalyst I'm sure costs $2000+ dollars + labor. That's why you see a lot of noise regarding P20EE, the dealership is just following instruction from FCA. If they don't follow repair instruction, may kick dealers warranty claim.
The dealership doesn't care if you looked up the code etc. , back in the day we would be annoyed with people giving us TSB's they would expect us to carry out the repair, like it was a recall, but 75% of the time their VIN wasn't on the TSB anyway; that's how you will upset dealer people, don't tell people how to do their job.