[vanir]

Quite correct. I encouraged all flight testers to use any and all available means to the pilot. Technically combat flaps and open radiators should lower sustained climb times, but then half fuel load raises it again.
Actual adjustments are based on my own flight tests using standard operating procedures and strict historical documentation, but the valuable information from flight testers is a guide on where to concentrate, saving me several hours.
Generally the best way for testers to judge the comparative performance of aircraft is to fly in the style they are used to, I can read between the lines.