Just joined to answer a few questions I had input for. I thought the Army had a lot of acronyms but daggum this place has it beat. Anyways, I'm a 2014 grad that took an extended stay because 54 months is better than 47.
It can be a whole host of things from a medical issue to an honor board. I fell somewhere in the middle. For me, ramification was I worked the CST TOC all summer (a valuable experience) and was moved back a yeargroup for promotion. Outside of West Point, it has not affected me.