[phenixbb] How to do a phenix.fmodel calculation incorporating the exponential scaling model only?

Hi, I want to use phenix.fmodel to do a calculation incorporating the exponential scaling model only (Not the flat model). I am not sure whether I just need simply specify: mask { use_asu_masks = False } since the output maps are just identical no matter use_asu_masks = True or False. Should I do something else to enable exponential scaling model only? Thanks! Best Regards, Hailiang