First just a note on formatting your DAX measures in posts - https://forum.enterprisedna.co/t/how-place-dax-formula-into-forum-topics-posts/156/3
When we jump to this sort of logic it gets complex fast.
Is it possible to just focus on one here.
Which calculation would you like to look at. I can see Continuing students isn’t working? But the new students part of it is, so what’s unique students calculating?