I just went out and measured my Scamp's ball height parked level in my driveway. It is 19 inches high.
I went out and measured my receiver on the Odyssey. The bottom of the receiver is 13 inches off the ground, probably different from yours.
My ball is 20" high unloaded by the trailer. When I sit on the rear bumper of the Odyssey it drops about 3/4 of an inch. I weight about 10#s less than our tongues 200 pound weight. As a result the back of the Odyssey is about the same height as the trailer when level.
I must say I haven't towed with the Odyssey but will this weekend. However the receiver and ball are from our former tow vehicle and the numbers seem almost identical. If I have any issue I'll let you know.
The following is a picture of our ball, note how close it is to the rear bumper, as close as I can get it, reducing the distance from ball to the rear axle