Was your install supposed to be completed in 2020? I thought most of these loan balloon payments were tied to tax day, and 180 days would make a bit more sense for something installing late in 2020. But as it stands, you will likely need to pay the increased amount, or, if you can work with the finance company, they might defer the increase, but I'm sure you will still accrue interest. If the install actually completed this year (and I am not necessarily talking about PTO, but when the installers finished putting everything in) then you will not get the credit until you file your 2021 taxes in 2022.