It's not something you should spend time worrying about at all. A couple of my CS stats are lower than what Etsy wants them to be, but it's only because I sometimes do things in a way that Etsy can't track. As long as you know you are providing good customer service, don't worry about those numbers.... BUT if it really means something to you, maybe it's possible to just put in some random numbers in the box and somehow select "other" as a carrier. I don't know if it's possible, just came to me as a maybe. But then again, that's not actually tracking!