generally if the school is normally on a semester system or quarter system... the credits are always semester or quarter respectively..no matter if its fall , spring , or summer..... it doesnt matter on the length of the course... considering what you have told us... and like what someone else had mentioned... I am almost certain that Ochem class over the summer was 3 semester units... so if on a normal fall or spring schedule at that particular school is semester... then the summer credits are semester too... shoot whats the school name... i'll call them up for ya 🙂