A:Answer we just had Geek squad install this unit, it fits perfectly with the KitchenAid microwave top edge being 34.5 inches above the counter. The lower edge of the microwave is 19 3/8 inches above the counter. This leaves still 2 inches of cabinet left and right to extend lower than the base of the angled side section. We have some extra tall cabinets and fed the power cord through the base of one of the two cabinets above the microwave, looks perfect.
You just want to make sure that the rear of the microwave, lower edge, covers the subway tile top edge or wall material installed behind your cooktop (don't leave a gap). The 30 inches is not enough to allow the microwave bottom to clear a tall pot of boiling water you may use for pasts and you don't want the steam to be right below the fan area on the bottom of the microwave, that can lead to internal condensation onto the electronics boards resident in the door.