The DS can also be a lot more expensive if done in 2 parts as there's scar tissue to get through, so be sure you know what you'll be paying as part 2 could be a lot more expensive than just the sleeve as I found out.
The DS is one procedure. Doing it in two steps is not a true DS. There is a synergism that happens when you get it done in one procedure that does not happen in a two step procedure.