Did you get your question answered yesterday?
The updated USDA video on how to figure corn bu, https://www.youtube.com/watch?v=mGXl7dr8kaQ, still seems to figure 1/2 the remaining unsold bu after Jan 15 times $0.67, and now times .80, to figure your payment. The other .20 is not spoken about. Maybe that is for the USDA to keep?