Apparently most of the problem with SBC when I talked to them earlier didn't have much to do with their policy being strange. It had more to do with the rep I dealt with forgetting to mention a detail to me. The detail he failed to mention: if I pay for the one additional month of DSL service, regardless of if the DSL is connected, they won't charge me a termination fee.
This makes much more sense than what I was told before. I guess the moral of the story is that it's worth calling back when things just flat don't make sense.