The P4 was discontinued supposedly, at least for a few months. It wasn't available on their website, and if you called the in-store staff said the computer displayed it as discontinued. the staff were not very knowledgable on the subject, but most stores still had old P4 stock in house. thats the story I gather after calling a few Sears stores in my area....some said it was discontinued but you could still buy what was on the shelf, some had no idea what i was talking about.
maybe it was just a manufacturing/supply issue, or maybe they really did try to discontinue it but after they looked at the purchases they realized discontinuing that battery was a very stupid idea