I don't think there's much of a difference in terms of what happens to the player. It feels more that the first two selections will make the club, then you have two "wildcards", which can be chosen from anyone else that signs, whether that's second, fifth, 10th, or 15th round.
For example...
Windsor has signed Belchetz (1), Lemieux (2), Hicks (2), and now Windbiel (7). Belch and Lemieux will make the club or be carded (memory is slightly foggy to that clarification). Given Windbiel is American, he's likely going to make the club, too. So now they've got Hicks, plus whoever else gets signed... likely one spot for them, while the rest head to Junior B. If they get Garden, he would be the one who makes the club.
If they have Hicks, Brocklehurst, Robinson, etc. in Jr B, plus Belchetz, Lemieux, Windbiel, and Garden on the roster, that's a pretty darn good draft.
It's a long way out and a lot can happen but that's how I've interpreted it.