Going back to revise a game is a good time to make a clean new plot map but mostly with JV (the revision) I have bene thinking pacing and punchups and combining them by pulling in a chunk of the B plot line to speed up a weekend long relaxing game from 3 hours of a 5 hours game to 4 hours of the 5 hours of plot. And writing another hour of plot in case the players supprise me.

Always have an extra hour or two of plot. Albeit once you build a real world it usually writes itself in broad.