Is it okay to fire ceramic glazed ware and greenware in the same load?

Do not fire glazed ware and greenware in the same cone 04 kiln load. This is because not all glazes are fired to cone 04--only specialty glazes such are bronze (metallics). There must be a 2 cone difference between bisque and glaze firing for good body fit. Otherwise, the glaze can separate from the bisque and peel off.