It's not presented in a usable fashion, but the existing Pro tiers are having their storage doubled with price held constant (50GB @ $10, 100GB @ $20 --> 100GB @ $10, 200GB @ $20). They're also adding an additional 500GB tier above those, which we don't know the pricing of yet.

Bad presentation on their part, but hopefully that answers the question [that people would have when clicking the link].