Thanks Wayne, good to know.
Unrelated question, but I've been curious about these situations... in that pic above, the closet bend arm is perpendicular to the main drain line below. The main drain slopes down to the right (not visually in the pic but in reality it slopes down to the right). If you rotated the toilet flange 90 degrees counter-clockwise (looking from the top) on the vertical drop/vent stack, you would have that short horizontal arm after the closet bend directly over and parallel to the main drain, but sloping in the wrong direction, correct? Would this be allowed? Does code specify the allowable orientations in this case?