Ford doesn’t try to make it work for every vehicle out there while Curt did. Fitness RV did a test and it wasn’t very good results. The engineers came out and did some work to try to make it better.
My guess is that Ford’s solution “could” be far more accurate although not perfect over time. Springs do change over time.
For me though, I’m not sure why I care other than having the latest tech gadget. Not that I’m against tech as a person who retired from it, but at some point, you are paying for gadgets that rarely have a need. For instance, for this “feature” what would you do if you found out that you were x% higher than you wanted to be. Maybe the first time, you take stuff out. After that, I think most would just go for it. That’s about equivalent to going to a CAT scale once, but of course, the Ford solution would be far more expensive.