I cannot imagine that you will ever run across a sewer connection that is higher than your tank bottom. As long as the tank bottom is higher than the sewer connection it will drain. I had a Starcraft (Jayco sister) that was very low and often ran into a situation that my outlet was lower than the dump inlet. It really didn't matter since the tank was higher. Gravity will empty the tank.
Now there is an issue that the fluid does lay in the hose. Just make sure that the hose is long enough that once you hear it stop draining you can pick up the hose near the trailer(leave connected) and "walk" the lifted hose towards the dump. Lay it back down it will refill and repeat a couple times. The last of the remaining fluid will drain. Yes this takes a few attempts but it is sure easier than putting the trailer up on blocks and needing to carry the extra blocks.