Make up has a few meanings. The meaning there would go with "for the last time." would be "becoming equal" or "repaying".
If things went wrong, this time the speaker plans to have an extra good time.
If the other person payed for something last time, this time the speaker will pay.
If last time someone cooked, this time it will be the speaker.
If the speaker lost a game last time, this time the speaker plans to win.
In the end, this time all will be equalized.