Briefly running 2 servers with the same license

I have a question regarding the photon in-premise server quantity policy: In our game, we've implemented a mechanism that allows us to gracefully move our users to a different server without killing the server mid-game. This means that for a brief duration (approx. 5 minutes which is the duration of a typical game) some users may still be playing the game on the old server while the new server is up. Do we need two server licenses even though we only actually use one? Will the license check even trigger or does it have some sort of a grace period?

Thank you!