There are two different kinds of UNSATs in MPTS... sort of... very bad UNSATs and regular bad but still bad UNSATs. There is also still Marginal.
A flight that used to be one below will still be a flight with bad grades under the new system. An old system "two below and one above" flight might be marginal now (shot across the bow). A flight that might have been a marginal in the old system might be the lesser kind of UNSAT now (plenty of attention and death by counseling but usually keep pressing) or it could still be marginal. The wrong combination (two in a row, etc.), getting shot on a checkride, failing an academic test, or getting a ready room down are all automatic extra special attention. Also, the squadron CO always has the discretion to give a student "extra special attention." Sort of like that- but this is the short explanation.
Special policies come and go over the years- three strikes you're out, one strike you're out, 5 UNSATs or 5 UNSATs plus Marginals you're (probably) attrited, xx NSS and below gets flagged, etc.
Completing flight school now with MPTS grades meeting the minimum absolute standard (the infamous "MIF") while saying that NSS doesn't matter and you're prepared for the FRS and the fleet is like barely passing your driving test and bragging about your shiny new license. It's also like getting a diploma for a D- average. Seriously.
Hope that helps. Clear as mud?

FlyBoyd or one of the other experienced TRACOM guys, can you weigh in?