Sorry for replying so very late, I only just noticed this topic.
I remember getting an insane ammount of rating teh first 2 days. I don't remember if it was 25/win but I do remember having 1 loss and about 20 wins, jumping right into the top 50 somewhere. At that point I had a 1 day old deck right in between the 3-5 day old decks.
Rating/win really jumps up and down alot like that. I assumed this was the case because very few people played Platinum League that day and were each worth ALOT of rating because of that. I was just lucky enough to get alot of plays that day.
I never did get that first rank though afaik.