Have you tried to contact Crunch Human Resources in the Portland area?
I think their pay depends on the certifications and degrees you are currently holding and by the number of sessions you do per week. I believe it’s different for each city. This information is based solely on an interview I went through with them when I was checking for new places to work at, some years back when I lived in Chicago. They might have changed their pay structure by now.
It also probably depends on locale (most do). So while the percentage may be the same across the gyms, the dollar amounts may be substantially different.