Towing Level?

The dealer installed my hitch on my vehicle when I picked up my TM. I questioned the height of the hitch being so high and he said the trailer should tow higher in front than back. I seem to remember it should be level, but I am not sure. Should it be level?

The tongue is 19 and 1/2 inches high when it is leveled and not hooked up to TV. When it is hooked up to TV, it is 20 and 7/8 inches high.

Thanks

Walt