Just a guess, but if the minimum overpass height is 13 feet 6 inches, I would think the 13 feet 1 inch number should include the A/C's. Otherwise it might not fit under many, many bridges.
If the need arose, would you consider removing the A/C cover(s) just to pull it in?
I have had the covers off my A/C units a number of times to clean and inspect. It was a piece of cake.
I would be more concerned about low tree branches.