[Sir Folds A Lot]

I just read Harrington II and according to his section on heads up, you should always complete in the small blind with any two cards. He says to do so in heads up, but his argument is that the pot is giving you 3-1, so you have to. I have to assume if their are better odds made by more limpers, you would have to call even with 72o. Am I interpreting this wrong?