I saw the $400/hr in some article that I can't find now but this one from the SF Chronicle explains how the total work involved is more than just four two-hour sessions:

https://www.sfchronicle.com/bayarea/article/California-math-...

"The Oxnard district training or others like it don’t include only the time in front of teachers or at the district, but also about 18 hours of preparation, Boaler said, which isn’t specified in the contract. The deal also means significant travel time."

It's not uncommon for consulting to work that way where you pay $X for a report and a couple hours of presentation but theres a bunch of behind the scenes work you're implicitly paying for too.

So her effective rate was probably a little over $1k/hr. Doesn't seem that unreasonable for a Stanford prof.

Boaler claimed she needs 11 hours for each session-hour.

If you believe that (e.g. if you think the sessions are heavily customized for each school district, and not just the same thing at each place), then you'd divide the 5k by 11+1, getting $417/hour.