If you pay to upgrade now, no you won’t have to upgrade again when it’s out of beta. You can install it when the gold master is released and your year of updates starts from the time of the final release.
I’m wondering whether there’s a bug in the licensing page. When I log into my account, I get the message the “Your Licenses include 2 that are past their prime”, but so far as I can see everything is up to date. It’s possible that the two versions I upgraded from in the past may be being counted in the total, despite being (correctly) greyed out.