I don't get it.
DRG indeed has 12 JAs, but 2 of them share recast timer. If you consider the number of job abilities with separate timers DRG has it should be 10, not 12, no?
And what about Samurai? (has 13 job abilities)
What about Thief? (has 13 job abilities)
I don't get this.
Unless maybe 2hr abilities are not considered part of the 12 group.