Welcome to our forum.
Disregard that technical stuff. It's relatively meaningless to average consumers. As you found out, what really matters is your comfort in the spa. Keep trying them out, and stick to one which feels best to you and your family.Brewman
Good luck. I found a hot tub was one of the smartest uses of my money in a while. I have definitely seen a different and better quality of life since owning one. -Ed