My math was fine, we're both right, do you see why? (hehe)
I used an odds ratio you used a fraction of the total AFTER the call.

A little pokerstove action:
If I have pocket dueces(scoff), and they call with AA,KK,QQ,AKs and AKo, I'm 34% to win, which is positive since my money makes up 1/3 of the pot. Add AQ and JJ to the range and I'm almost 40%.

This is all theory, and I don't think I'd do this on deuces, but I'm hoping for some good thoughts on what kind of guidelines you would need for this move. I think the deuces example really only works if you're AI or can read your opponents god-like after the flop.

Position is also a big thing here. If you're not AI, and in the blinds, you really can't play with the idea of showing down an unimproved pocket pair that isn't an overpair to the board. From late position you'd have more options.