My gym bronzes do 6 hours, silver does 8, gold/platinum does 12 and Diamond/sapphire does 14. We use xcel as a replacement for compulsory, so after gold or platinum you can go to optional or stay xcel
At my gym, I think its 9 hours for silver (not sure), and 12 for both gold and platinum. No diamonds currently but when there were, they did 16 hours. I don't know about bronze.