You might not be happy to hear it but if you've already got the DLC Pass, it won't make any difference.
The Season Pass cost $20 out of the gate but that price will rise to $30; this is a result of an "increase in scale" in the aforementioned expansion. The Following will move from $15 to $20. As the team said in a statement:
"Over the past weeks, Dying Light: The Following has almost reached its final stage: main quests, side quests, new skills, and driving challenges are ready. We now are moving into the polishing period. Looking at it, it's clear how big the expansion pack has grown–it could be a standalone title, but since it would mean a launch delay, we decided against it.
However, due to the increased scale of the project, we needed to revise the pricing that we announced back in August, and so we want to let you know that Dying Light: The Following will be priced at $20."
These price changes will go into effect on December 8. If you've already got the Pass or you decide to purchase it before the 8th, you'll pay the old price of $20. Better hop to it!
Related Game(s): Dying Light