There are two "kodak methods", read the entire test!
1. is running water for up to 30 minutes, which really ain't Kodaks method at all, but the traditional method.
2. is 10 changes of water, compared to the Ilfords 3 changes of water.
Ilfords method is sufficient with non-hardening fixer, which is more or less standard issue these days.
10 changes of water is enough for anything.... usually more than enough.
The interesting bit in the test was a glimpse into how efficient running water really is, in theory its not efficient at all.....
But as said before, I prefer my "adapted ilford method" at least 6 changes of water and usually one or two more with a drop of detergent added to get rid of water droplets. My negatives will outlive me by a good margin.