I take it that you are concerned about "high centering" at the top of the ramp where it hinges with the floor. You can reduce the angle between the ramp and floor (a little bit), by placing a set of these under the ramp when it is in the down/load position. Just center yourself on one of them and do it.
Alternatively, you can lay one of these loading ramps on the trailer ramp and it will "see saw" as you pass the apex point and prevent a high center situation.
But you'll have to be brave to do it. And you'll have to strap the bike down while it is still on the loading ramp (not a preferred procedure).