Yes, that's why I said "about" 180 degrees, I didn't think the difference of a few degrees was important. The reason I did mention the difference between that and RD ratings based on "whole" rings, is relevant to RD selection, if the OP needed to change that in the future; If they are considering changing chain length, verifying RD capacity is a prudent move, rather than rip off the cage or not taking up the slack, and a lot of factory systems come pushed to the edge of maximums these days. This is something I had to verify myself, when I was upgrading my bike from 1X to 2X crank, and I knew (from career in mechanical engineering and a chain/twin-sprocket device I designed to stabilize from swinging and maintain orientation of a moving platform) that the chain difference is based on an approximate half-wrap; I had to look on Sheldon Brown to see if rear derailleur capacity ratings were based on that, or "whole" chainrings and cogs, and it was the latter, though inaccurate, but that's the way they are rated, so that's what I needed to know, and it would be relevant to the OP if they change rear derailleurs. Based on the OP's question, it's clear this may be an "unknown-unknown", so it's appropriate, generous, and helpful to say, "Uh, hey, watch out for this..."