Hey! I was told in a mass email sent out on March 13 that Tabbatha would be in touch in April, "likely mid to late" with an update on second round admissions, so it sounds like the waitlist notices are going out in waves with different dates for anticipated updates. It could just mean they're waitlisting throughout the first round and adding a few weeks of buffer time for people to hear back between each wave of notices (i.e. the differences mean nothing). It could also mean the waitlist is ranked into sections and the earlier you hear back, the better. I don't think there's a way to know for certain yet.
But either way! People with GSPIA acceptances will have to answer back quite early in April, and I imagine many people applied to both schools. They're all going to want to know for sure by then if they should go ahead with GSPIA/some other school. if you don't hear back before April, Odessa, you should call or email NPSIA in the first week and see what's going on!