Adam,
I have no idea what they're trying to do. First, using only 2 levels of support and resistance is useless. Second, their computation, even with their formulas are wrong.
They probably are trying to align on freestockcharts because I saw that they added VWAP too.
I don't recommend relying on their pivots as they are displayed now.
Many sophisticated variations of the formulas have been introduced over the years and most were only marketing gimmicks. What I'm sure is that the classic formulas are working perfectly for setup planning purposes so I don't see any use deviating from them. Stockcharts is an excellent technical analysis resource, but not a very good trading resource.
Billy