It's always better, I think, for people to get that DO letter of recommendation.... but just because you don't get a letter of recommedation doesn't mean you won't get that interview.
So to directly answer your question, I don't think that not having a DO letter will prevent one from at least getting an interview.
There are others in this forum that can attest to that. With those stats you present, I can't see why you won't get granted an interview.... Good luck.
