DS is an MS2 in a STEM major at a school notorious for impacted programs. Even with priority registration, his major’s demanding curriculum, plus the addition of MS classes, make it challenging to graduate in four years. And that’s with some summer school and priority registration. My understanding is that the Army will pay for four years flat, and that he’s on the hook for any extra time. For example, the Army is not paying for the two summer classes he’s now taking. (On the plus side, his major earns him a small but meaningful boost in OOM.)
To be sure, check directly with your chain of command. Things can differ and things can change.