Most successful upside down cuttings that I have seen have eventually sent a shoot up for a bud that is beneath where the roots formed, so that the direction of sap flow is correct, even if it has a loop in is. That is to say, the a bud deeper in the soil than the roots, which would have been higher on the cutting if planted right-side up, and thus above the roots, will send up a short (if there is a viable bud to do so), and that shoot is now in the correct sap flow direction from the root, and will perform fine.