1-2-3, if you look closely, actually has a sheen to it, somewhat like an eggshell. That being said, if you covered it with a flat ceiling paint, it's like painting flat over satin, so yes, two full coats, IMO is gonna reduce that flashing of the primer. Be sure to really load up that roller and put some paint on that ceiling. Your roller cover should ALMOST be dripping with paint before each pass on the ceiling.