I already have a nice, and expensive, 15A power cord that I like and matches all other cabling in my systems so I'd rather not have to buy another expensive power cord of a different kind and options for 20A to 15A are limited. But, the cable manufacturer is receptive to custom modifications so you bring up a good point and maybe I'll have them replace the 15A female connector with a 20A. That is probably the path of least resistance.
The annoying part is that if I move on from ARC, I have a next to useless power cord that I'll need changed back to 15A again. "First world problems" as they say.
Thanks!