From the one Limdu person that I worked with that got out from the Navy it was because he was found fit, but not world wide assignable ie no IA billets or nonconus billets. He then had the choice to stay in, cross rate, and possibly go surface or a shore comand, or seperate. He chose on his on to seperate because he was limited in his assignability. He was a nuke though, and is making more outside in a civilin nuke job then what he was making as an E-6.