If you go to the Simpson Family Tree DNA project page and study, you will find a great deal of information and get some insight into the Simpson family.
I am seeing Ancestry and World Connect trees on the web thatdon't have the DNA matches. People are mixing families with similar names and dates.
Sometimes it pays to look beyond what you think is factual, to go an extra mile. Hey, folks, it takes all of us to do this. If you see your family doesn't have DNA posted on the project page, then round someone up and get a test scheduled for Pete's sake. You might find a few cousins and share the cost if all else fails.
I don't see any other way to correct the genealogy of a common surname like Simpson. Otherwise we will never be certain that we have our genealogy right?