Loan Rehabilitation Question for Small Loan

In a niche situation with a relatively small loan of my husband's ($2k total principal and interest) that, as far as I can tell, could go about 4 different ways depending on a couple of factors.

This small Perkins loan surfaced about a year ago (he wasn't aware of it) and is now in default. I would like to go through Loan Rehab to get the default line off of his credit report, but there are 2 outstanding questions I have before I submit the paperwork:

1) Everything says you must make "Nine Consecutive Payments", so does that mean for a loan this small, they would take the full amount and divide by nine to get the monthly payment? If they use the discretionary income calculator, we would more than likely end up with a monthly payment amount that is higher than the $225ish that would come from splitting the loan into nine equal parts.

2) What income amount do they use to calculate discretionary income? Because of my student loans, we file as Married, Filing Separately, so there are about 3 different amounts I could see them using: his taxable income (the lowest), his Adjusted Gross (middle), or our combined income (MUCH higher). If they use any amount other than his true taxable income, the payments would be too high to last for nine months.

If anyone has any experience on these fronts, I'd love to hear about it! Thanks!