You might want to try guiding the fabric while it rolls up. It helps to have two people, i.e., one on the other support, while you guide one end.
Slowly let the spring retract and wind up the fabric while watching it roll onto the roller. Move your support side-to-side, as necessary, so that the end/edge of each layer lines up with the preceding one.
With a little practice, you'll be able to have all the layers lined up like you had cut the end of a roll of fabric. This should make the end caps, supports, etc. align properly for an easy stowing of your ZipDee awning.
Additional tip: After we get the locking wheels tightened, and the locking hook is rotated into position, I put zip ties through them so that they cannot loosen while underway. I leave the long tails on the ties, instead of cutting them off, so that I can see that they are still in place. This provides an easy visual check to verify that the hardware is still tight when inspecting your brakes, hitch, etc. and while refueling.