You don’t. Flats need a bias master or a flat-dark master, not a dark master. In Live mode, if you select a flat master to apply, the ASIAir will make you select a bias master as well. If you want to use flat-dark instead of bias masters, just tell the ASIAir you are creating a bias master but expose it as if it was a flat dark.

Doubling up on a discussion in CN as well but does that mean ASIAIR does NOT create a Master Flat in auto mode in the Live Stack section (as it claims) but instead just a consolidated set of flats which the software calls a “Master Flat”. The consolidated flat is then selected along with the master bias and the master dark during imaging and the software “creates”the master flat on the fly. It then applies this to the image process? If you THEN want to use the stored “master flat” on the USB in later post processing (assuming you save all the light frames) how will this “master flat” work if no bias was used in its creation? Puzzled by this!