Maurice, Mabula – When I was using a DSLR, I also liked to capture my lights at ISO 1600 and Flats at ISO 200 (longer exposure means that each flat has better SNR). What I would do is to use Bias frames at ISO 1600, and flat darks at ISO 200 (and, of course, same exposure time as my flats). I had used Images Plus for calibration, and it would default to applying the flat darks to the flats. I presume that IP only used the bias frames for dark scaling.
Mabula – Would APP by default use such flat darks for calibrating the flats? Would this be a good method for Maurice to use?