Oh, thanks
"I think the original poster used "DD" to mean double down; to lose a double down on each of two hands twice in a row."
Ah, yes, that makes sense. Of course, without knowing what the specific hands were, that's impossible to answer. Some doubles have only a slight edge; others, like 11 vs. 6, have an enormous edge. And, of course, the dealer upcard matters, as well.
Don