Yeah, after reading Benchmarks & Optimisations (Matt's benchmarks) I tried both approaches (just specified one for brevity), and they had roughly the same performance dip. Its not super relevant since its already doing a single push to the screen, I was interested in it as a form of batching in the case it wasn't happening.
I agree there wouldnt be much gain for the final question.
A bit more context, the game I'm working on is sitting pretty steadily at the 48fps full-screen-redraw capacity of the system (on device), but its getting close (tetering around 80% cpu). This is with ~30-50 draw calls per frame (which comprise ~50% of the total frame), with a fair bit of other computation going on (collision detection, animation stepping, enemy spawning, level tile paging, sound tracks, sound fx). Does this seem like a reasonable ballpark for the cap on how much drawing can be done per frame?