Let me dissent just to keep the thread going. Hey, if topping off works for you, it's good. I'd make a distinction between topping off and parfait, since usually parfait is setting up layers of different tobaccos before you light up, or that's what would be generally understood. My reluctance to top off is that if I'm smoking well (to me) the bowl tends to develop and improve as the bowl burns, the ember becomes more focused, the flavor more nuanced, and the burn more thorough, if I'm lucky. Starting "over" by packing new leaf on top diminishes that effect somewhat, for me. I'd rather smoke the bowl down to dottle or white ash, and repack another.