CSAT is not standardized and there are many ways to calculate it, one of which you have linked. I've seen firsthand many of the largest brands calculate it differently.
That "measures the satisfaction of consumers across the U.S. economy", very different from Brand's Customer Experience Surveys. Having worked as a software vendor in the CX field, I saw a lot of different implementations of the "same" survey metrics. NPS was only standardized one (I think because its from b school in the 80's).