I cannot help but believe you should recast the mortgage while you still have ample income from a job to report.
Just my own experience: Absolutely no paperwork was required on my part other than signing a single document saying "yep, re-work the numbers". The only requirement is that at least $20K in payments has to have been made at some point, otherwise, there's no point in re-amortizing.
I'm self-employed, so believe me, I know when someone's trying to check my employment status.
My understanding of re-casts is that most banks offer ONE free of charge because many people take on a new mortgage before selling their other home, then when the other home closes, they want to roll the proceeds into the new home. It's what they would have used for a downpayment, had the first home closed first. So it is in the best interests of the banks to allow this practice, just to keep sales moving easily and so that no one is holding up a chain of sales because their house isn't sold yet. So I think they intend for a recast to happen within 30-90 days, but I didn't do mine until a couple of years into mine.
I have Wells Fargo as my mortgage loan and they seem to allow unlimited free re-casts, but I think I'm done. I've reached a payment that I'm comfortable with.