CMMI is completely senseless for an organization of one developer. That being said, government contracts are known for senseless requirements designed by bureaucrats who have no actual interest in the efficiency of feasibility of the requirements they impose.
I don't have any hands on experience with CMMI, my only brush with it was to get the idea of implementing it scrapped in favor of more sensible agile development models the last time my company decided to change things up.
I do, on the other hand, have some experience with subcontracted IT work when the main contracts contain absurd requirements. I would recommend looking carefully at the contracts as the first step. Determine exactly what exactly the contract is specifically demanding. Must the appraisal come from a designated appraiser or certified appraiser? Is self appraisal a possibility? There's a chance you or your sub can just BS your way through this with some extra paperwork and go back to do quality work and collecting money.