Recent reviews by Ford

If you buy this season pass and already own Sorched Earth DLC you will not beable to refund on steam as you will have surpassed 2 hour play time limit on refund request.

Even though you will have not played with any of the new content. It starts counting you playtime even if you just use the base game.

As there no way to preorder just the next DLC I bought the pass early ( cause generally price fluctuations ) and then changed my mind and found myself in-eligble for a refund of the discounted Season pass price I paid.

So Buyer beware steams automated system and an apparent lack of common sense will leave you out of pocket if you wish to refund something you have yet to play. Regardless of your reasons.