Why would you want to wrestle the 21 or the 17 all the way to the attic hatch and back instead of just folding out and extending the 13. Though I've found that with quite a few hatches, I can fold out and extend the 13, use the top of it to lift the hatch enough to rest the ladder. Then climb the ladder, finish removing the hatch, do the attic, climb back down on the ladder, reset the hatch, finish climbing down, and using the top of the ladder to lower the hatch into it's closed position. I seldom carry my 17 into the house, just don't find much of a need for it even with the high ceilinged houses. -