It is all about marketing, but from my own perspective I find it strange that upgraders from Production Studio Standard pay the same amount as do Production Studio Premium users. OTOH one can argue that the Premium users, even if in the past they have invested more than Standard users, have had the benefits of the Premium package.
The upgrade price for Premium users should be lower than for Standard users, something like $ 599 for an upgrade from Premium and $ 799 for the upgrade from Standard, but that is just my opinion.