yes
ok note that if this happens your loan is delinquent and late fees may be charged. Even if you are behind on your loan, you can still avoid default, so it is important that you contact your loan manager immediately.
Loan Consolidation is also something I'd like to learn about. What if I need to refinance a defaulted plus loan for my son's education?
The only income-driven plan you can choose is the Income-Contingent Repayment Plan (ICR).