APS Expertizing Service Errors?

If I can quote/paraphrase from Bob's Rules; also known as Robert's Rules of Order: Point of Order Please. Regarding references from some of you; e.g. Scott #901 vs. Scott #1053. Or Scott #230 vs. #245. Or an R133. Or, if they don't have a grill; a pressed out grill; flat plate coils, vending coils, certain revenues, and so on.

I'll offer that for those on this Forum who don't reside in the USA, it would be real helpful if you mention that you are talking about US stamps (unless you're not). I know what those Scott numbers refer to; what a "grill" is (no, it's not an outdoor barbecue apparatus). But lots of others may not, especially since this discussion is not contained within the USA section. Thanks in advance for your sensitivity.

This discussion is really about the US expertising services, which mainly do US stamps these days (although some groups did a lot of non-US stamps 50+ years ago).