If prices go up, does mine go up too?
No. Whatever Pro cost on the day you subscribed is what it keeps costing, for as long as you stay subscribed. Price changes apply to new subscriptions only.
Not for a year, not until the next review: for as long as the subscription stays active.
The one thing that gives it up is cancelling. If you subscribe again later, you pay whatever Pro costs on that day.
The terms say the same.