Dealer would have set the adjustable height to achieve the correct measurement at the top of the ball, when the shank is installed it the truck.
If the pictures don`t agree with what you have seen, could be the hitch was on a different truck ( 3/4 ton , 4X4,) any number of things could be different.
What is the height to the top of the ball with the truck on level ground ?
I think 17 1/2 inches is the height most aim for. Varies a little by manufacturer.
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.