三人行，必有我师(焉)

Didn't click 去 the article but offhand from your last bit, if I were calling someone a couple floors above me, I'd probably use 上去 in most situations unless whatever's upstairs is someplace both me and the listener have reason to view as going back to? Like, "hi I'm here to 拜年, coming up in a bit" is 上去 definitely, but "I'm seeing off a client downstairs, be back to our office (which is upstairs) in a bit" then either works – I'd probably pick 上来 but that's just habit.