It's not different, which is why it's possible to think of it that way without changing any rules. But it does mean that you no longer need to worry about "extra" turns. Rather than count the number of turns each person took, and then subtract the ones that counted as "extra", you simply look at who was the start player, and where in turn order did the game end. I mean, that's what people do in reality; no one is actually counting turns IRL.
I feel like it would have been much better to have this conversation in person, because I think there are some basic misunderstandings.
You're right that players don't have to count turns, but I never suggested that they do. But when the game ends in a player's extra turn from Possession, we can't just check where that player is in turn order. We need to specifically disregard that extra turn.
If Fleet turns count as extra turns, it means we can disregard them at the end of the game (and so just check where the game-end triggering player was in turn order, just like you said). If Fleet turns don't count as extra turn, it means we need a special extra rule to say that we should still disregard them when doing that. You can't
simply look at who was start player and where in turn order the game ended, because that would include the Fleet turns. You need that extra rule. That's all I was saying.
Like Donald said, the rule book does say that the turns count as extra turns. But I don't see why it's an either/or between that and creating an extra round.
Because if we count them as extra turns, we can't follow your 3-point model of extending the game with 1 round. The reason is that per normal rules the game-ending player would get their extra turn first, which is not how Fleet is supposed to work. So then we do need to add the extra rule that the game-ending player gets their Fleet turn last, and we don't need the extra rule that turns in the final round dont't count for tie breaker.
Fleet says there's an extra round, but that doesn't mean you need to start with player B. You don't just immediately end the current round because Provinces ran out, and then start the new, extra round. Instead, because the game is one round longer than normal, you keep going with the current round, and go exactly 1 more round; as in each player gets a final turn (but only players with Fleet, and those turns don't hurt you in the tie breaker).
So to try and diagram this; looking at a game with Fleet that only lasted 4 normal rounds. B buys the last Province on turn 4, and everyone bought Fleet.
Your latter case (not what happens):
Round 1: A, B, C, D
Round 2: A, B, C, D
Round 3: A, B, C, D
Round 4: A, B
Round 5: A, B, C, D
That does not follow my latter case at all. My cases were about Possession turns, and the latter one was in accordance with your explanation. I was saying that with Possession turns, it actually does matter if we add extra turns or extend the game with an extra round. I was thinking that extending the game with 1 round would mean that the game continues with the next player who would normally have a turn if the game hadn't ended (so player B in Ingix's scenario):
Round 4) A, B, C, D, E, F
Round 5) A, [B poss. by A], [C poss. by B*], B, C, D, E, F
Round 6) A
But I guess we could still follow the Fleet FAQ literally
("The extra turns go in order starting with the next player after the one that just took a turn"), and then it would be player D. The problem with that is that, following your preferred model, we get a round that doesn't follow normal turn order:
Round 4) A, B, C, D, E, F
Round 5) A, [B poss. by A], [C poss. by B*], D, E, F
Round 6) A, B, C
*triggers end-game