Paying my existing GC cash for remainder of the flip

[Robert Freeborn]

I originally put this in another forum, but I this may be the better place. I’ve been working on a flip in WA state for the last few months, and have been using a GC for it. We have spent about 68k so far, with about 30k left to go. The project is almost done with final expenses including paying granite, cabinets, labor for tile, final plumbing and electrical. So far I’ve paid my GC every week, with his invoice including his overhead and taxes. As we near the end of the project there is some concern that we are going to run into our contingency budget by a couple thousand dollars. My GC has offered to discount his fee and taxes if I pay in cash. I found and old post on here with similar questions, but it was more for individual contractors. I’m trying to decide if I want to pay him in cash for the rest and, if I do, what I should be aware of. The work I am paying him for has all be completed. So, to be clear, the work has been fronted. I know that 1) I need to get receipts 2) it could be a sign his business is in trouble and I should be aware of that Thoughts? Warnings? A