Players contract ends this season question?

[Accyrover]

If your player contract expires at the end of the season, the player will remain in your squad for 7 days after seasons end. During these 7 days you have an option to either resign him, or release him. If you want to sell the player, you must do it either today, or wait until tomorrow, resign him, then sell him.

Hope that makes sense

I have two players, now last season I could not get a concrete answer so I signed them with a few hours to go before the final whistle blew and the server shut down.
Are you 100% sure you get 7days to sign them up again?
Also does the signing on fee change.
EG. ST 20yo 5* 38, wage demand 120k signing fee 450k. does this remain the same or change as he will be 21 and lose a star and value tomorrow?
Have you actually done this with your players or just what you have heard?.