Payload for 2016 Ram 2500?? What am I missing??

Above is correct. Unless you are limited to class 2 10,000 rating, due to insurance or license fees, you just need to get the 35 series truck. In some cases the 25 series will have the same suspension, axle, tires, brakes, frame, etc. as the 35 series. No matter, it will still have 10,000 GVWR, with a lower payload.

Will the 2500 work? In most cases yes, but you will have to ignore some of the ratings.

Jerry