File this under “things you didn’t know because of sweeping generalizations.” Not all loans receive a grace period after you are no longer eligible for your in school deferment or status. PLUS loans (both parent and graduate) do not receive a grace period. For a Parent loan, the loan goes into repayment instantly after the final disbursement and for graduate loans after the student is no longer attending as at least a half time student.
In both scenarios though you can request what is called a Post Enrollment Deferment that will act as a pseudo grace period. This will give you the borrower 6 months after you (or your child for a Parent loan) drop below half-time status before repayment begins.
The other “different” thing that happens with PLUS loans only applies to Parent PLUS. As previously mentioned, or a Graduate PLUS, the loan will still go instantly into deferment when at least half-time enrollment is updated. However for a Parent PLUS, because many parents prefer to make payments, these loans start out in repayment status. If based on the student’s enrollment you wish to have a deferment, the parent must then make a request for a Parent PLUS In-School Deferment to be placed.