About Upgrading Ranks

So because of this double xp weekend going on right now, I've finally decided to buy a rank. Thinking of just getting vip as it's the least expensive and still gives me some good features. However one of my friends, who has a vip+, says that the jukebox and daily chest features are really good, and I like the re-naming crafted items so in the future I might upgrade. The store says that the rank prices are reduced if you're upgrading, but doesn't say what those reduced prices are (except for vip to hero). Does anyone know?

 

Here's the link to the store. Click on ranks, and you should see what the prices are reduced to (if you can't, VIP is 15 bucks, VIP+ is 32 bucks, and Hero is 64 bucks)

 

thanks!!