Propride installation Question

A question for you Propride 3p owners. I just installed mine and notice that before I hook up my truck I can move the hitch box by hand. The box will move 4-5 inches in either direction. Is this normal?

I have about 4 hours in the installation in 95 degree heat over 2 days. The instructions seemed pretty clear with no confusion but just wondering if I missed something somewhere.

Towing 26' Sunset Trains TT with 2011 Dodge Ram 1500 SLT 4x4.