Each tournament director uses their own structure for the length of the event. Once they reach the final table (6) WPT changes to one of their own structures. I believe they have an A and a B structure. The WPT final table structures tend to be much faster. I believe they are posted on there website and have criteria depending on stack sizes etc. for whether they use the A or B.

Hmmm. just looked. They used to be there, it seems they're gone.