Current child Support Order verbiage

Case is in Virginia. Last voluntary mutual modification to CS Order allowed me to include verbiage that once I separated from the military and started law school as a full-time unemployed student that the parties agree to a re-calculation based on the new income information. My understanding is that this verbiage weakens if not eliminates the claim for imputing my income in the next modification. My only "income" will be GI Bill tuition/fees paid and a monthly housing allowance. For tax purposes these benefits are not considered income, so would/could those amounts be used to represent my income? I've also included verbiage that any upward deviation in support currently provided would be considered towards future support amounts (I currently pay $1046, $100 more than agreed upon). Thanks.