PlanetsCentral

The status of the final turn does not allow, in principle, to update the turn.

Doch. (That's a German word that has no direct English equivalent.)

You can update your turn as often as you wish, even if it is marked final. The only difference between final and temporary is that temporary prevents host from running early - like you describe.

You can also change your turn from final to temporary and back at any time using the Options menu next to your race on the game page. (Do I need to add a disclaimer that this feature needs JavaScript?) For example, if you remember that you forgot something, you can set your turn to temporary so host doesn't run behind your back while you prepare the update.

--Stefan