Thank you for the nice compliment regarding the website!
The categories listed, as I am sure you saw, indicate both a "Recommended Minimum" and a "Recommended Normal" promotional guideline. That is exactly what it is meant to be....A "Guideline"! You cannot tell in advance that John Doe and Jane Smith will both develop on the same level, "even" if they were to work out at the "exact same" pace or have the "exact same" time in grade. It is simply a given fact that people progress differently. The bottom line is...It is not how many hours you spend training, as much as what you "Learn" while you are doing that training!
I hope that answers your question!
John Hiebert www.SeihokuBudokai.org