I thought the way this game played out was rather instructive, so I wanted to share it here.
Right before we arrived at this position, I could see that allowing the 3x3 would give me a positional win and I had a hunch that it was something that my opponent might go for. Sure enough, the game continued:
20-24, x, 10-15, x, 32-27, x, 1-6, 23-18, 6-10, 30-26(A), 5-9, 26-23, 12-16, x, 10-15, *21-17!, 13-22(B), 11-8, 22-26, x, 26-31, 23-18, 31-26, 18-15, 26-23, 15-10, 23-19, 8-4, 19-16, 11-7, 16-11, 7-2, 9-14, 2-6(C), 14-17(D), 6-9 etc. preventing Red from consolidating kings and making the win much more difficult with Bowen's Twins
A - 18-14 also wins, but I am a fan of out right gaining material
B - a common theme, which I have seen in one of Boland's books, if 15-22, then 23-18 steals the piece on 9
C - going for a 2nd King also wins, but this makes life much easier
D - in the actual game, Wayne went 11-7, as he likely saw that he was in a loss, but this allows 12-8 to an easy WW... clearly, Red can't go 14-18 due to the 4-8, x, 10-7 2x2 to a White Win
As you mentioned, I knew I was in a loss a few moves past the 3x3 and the note D move was just a way of giving up.