Extended – Graduated Plan

Who here has used the extended graduated plan as a repayment strategy? I recently switched and my beginning repayment amount is $257, max amount is $468 at the end of the 20 years (I entered repayment about 5 years ago). My calculated accrued interest in a month is $246. My work pays $200 towards the loans monthly through the section 127 allowance. I can’t direct where these repayments go, unfortunately. Once all my unpaid interest is paid, the $200 should go towards principal, correct?

Right now I’d like the lower payments so I can put the money towards other things – like paying down my car. By the time the payment increases in two years my other payments should be lower… and I’ll still have the employer contribution. Does this make sense to repay the loans? If I continue to allow the employer to pay the extra every month, I should pay them off before the 20 years.

Other question is… is there a calculator that I can enter my loans and repayment strategy with extra payments and the effect they’ll have? I’m a fairly visual person when it comes to these things.

Edit to add: I do have about $300 in unpaid interest from in school deferment left on one loan. That should be gone after next month.