Turns out bitbet.us may actually be in the wrong here! My Little Single is getting 29.4 Gh/s with a firmware update.
In their defense, the bet could be argued to require +/- 10% as delivered (eg, disqualifying firmware updates), but if this performance issue had merely been my software, they'd have defrauded people...
WOW. What gall. Glad I've long since stopped using BFGMiner and switched to CGMiner. Every time I read a Puke Jr. post I throw up a little.