Selling our house and the buyers wanted us to have...

Selling our house and the buyers wanted us to have the furnace and AC professionally cleaned. Genz-Ryan came out and refused to just clean, insisting that he'd have to do a full inspection and tuneup because it would be unethical to just clean them.
Did his thing for two hours and then told my wife that it would cost about $1,000 to fix the AC which was the most needed repair. She refused any repairs and he left and then emailed us the report. Multiple red squares were on the report stating fault this and fault that. Some others were orange boxes. This was on both the AC and the furnace! The faults were also listed out on the invoice which stated that we chose to not do any repairs.
When the main office was called and they looked up the ticket, they stated that all readings were within spec and that NOTHING should have been listed as a fault. They said all furnaces and AC unit would have similar readings.
So how is it unethical to do just the cleaning that the buyers and sellers agreed to, but it's ethical to use red and orange alert boxes and list out faults that aren't?
I knew that having them come out for a $30 per unit cleaning, inspection and tuneup would be risky. They don't make money spending two hours at a job for $60. So of course the tech has been trained to find everything he can to charge and they use company supplied forms with scary red and orange boxes.
Genz-Ryan won't be hearing from me again.