Uninformed suggestion (I dont know AB)
Maybe the x2.8 factor for the actual "G+Y" case already includes the factors for Direct law and for the config, so you are in effect double accounting (or even triple accounting, if you added them all)
certainly in "our" AFM/QRH when we have a failure case that "causes" others we try not to make you go flicking through the books, but rather roll everything up into the single case.