While I agree that there your weekly limits are accurate, I honestly don't think the random NPC is like that. I think it's a server load throttle. Obviously, I have zero expertise or proof of this other than their instance queues in Stormblood broke on launch and a little bit throughout the expansion also. If it is a server load restriction, they really, really needed to post a NPC with a schedule instead of pretending it's some new fun thing.