I've worked in government, and when we were asked to generate reports, there was a conclusion that they wanted to draw and they were looking for data to back it. If you ever hear something like "during the Carter era" it's likely because that's the only time the data showed what we wanted to make a point.

In this case, I would need to see why they chose 60 years rather than say 100 years. 60 seems like an arbitrary number that needs to be investigated. They may be right, but having read their pitch, there are a bunch of red flags that scream that this is ideologically driven rather than actually being "fair".

I'd be interested if someone did a deeper analysis.