Heather,

I work a job where overtime is available but never guaranteed.  Accordingly, in some years I may have none or very little while in others I may have more.  Instead of using AGI can I provide a copy of my pay stub - one that does not show any overtime - and have my IBR payment calculated using that information instead of the AGI from my tax return?

Additionally, I would like to increase my thrift savings plan (TSP) contribution.  I am currently at 5% but would like to increase it to 10 or even 15%, if possible.  This would, of course, significantly reduce my taxable income and likely make the current year’s AGI less than last year’s.  My IBR payment will be recalculated next month, so can I increase my contribution now and provide a pay stub with the extra deduction and therefore have my recalculated payment based off of current taxable pay as opposed to last year’s tax return?