A suggestion on how to determine the actual height of your 5th wheel.
When you have the 5th wheel loaded as you will most likely use it go back to the dealer where you purchased the unit. Make sure tire pressures are at you towing pressures.
Pull into one of their stalls and stop with highest point under the doorway. Crawl up on top and measure the distance from the highest point of the 5th wheel to the door opening. Then measure from door opening to the ground. Do the math and you will know the exact height of the 5th wheel.
I did this before I took delivery of my 5th wheel to make sure it would go into my shop building. My dealer was more than willing to do this for me.