This reminded me of our experience with Gusto - we signed up to their R&D credit payroll offset service in May last year - their offset fee is calculated as a percentage of the benefit you get. We filed our federal tax return in September, so there naturally wasn't any payroll offsetting until October. They still charged for services they didn't deliver so it was more cash out on day one which really goes against the purpose of the tool. They argued it was in the small print that said "we charge when you sign up" when I ticked a box. I thought that was quite outrageous. I still do.