That's the way it works around here too. Gotta be from the bottom up, but could be either doubles or singles so...either #3 dubs...or both #1 & #2 singles.
I've been on a team that received a #1/#2 default. And, even though we also ran the table with all three doubles, that lineup decision was not well-received around the league. As always, there was more than met the eye...as to why things transpired the way they did...but still, it wasn't an easy pill for some to swallow.
A 3.5 masquerading around with a 4.0 mask on.