I mean this:
EMocc = MaskOcc > 0 ? C_luma.MMask(bak, ml=MaskOcc, kind=2, gamma=1/gam, ysc=255, thSCD2=SkipOver).mt_inpand() : Blank
EM = MaskOcc > 0 ? EM.Overlay(EMocc, opacity=.4, mode="lighten", pc_range=true) : EMEM is "SAD mask (kind=1)" plus "Occ. mask (kind=2)".
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> So yes, 20/80 gives better result.
Did you tried it for *5/2 FRC rate?