Not at all speaking for the Andersen.
The B&W system was designed several years ago when the bed steel was thicker. It is a designed system. B&W sent me spacers so the base will directly press down on the bottom of the bed corrugation that is attached to cross hat channel rails that sit on the frame. There are two that are centered 16" or so apart directly under the hitch.
On my 2011 RAM the support PC of the hitch sits directly over the low part of the bed corrugation. So with my heavy load the base actually had a small tweak in it. B&W sent the strips and a complete new base. I installed the plastic strips under the new base and have had no further tweaking of the base.
Since, they have redesigned the base and do provide strips that can be aligned under the base for full contact. It has gone from a 18-20K rating and from 4,500-5,000# tongue rating.
Bottom line times have changed and I am pushing the limits of their original design that was based on older bed corrugation locations. Now with the strips I have no problems.
The same head portion is used on all B&W hitches. The base and attachment system makes them rate differently.
The RAM truck for example has the 4 puck attachment system as an option. Install the RVK3600 and it will have a 25K tow and 6,250# pin rating.