One other consideration is that in most parts of the country it's much colder now than it would have been 70 games ago. I know here in Utah we haven't changed the oil pattern, but the lanes play about 3 boards tighter than they did in September-October.
Outside temperatures can have a big effect on how the lanes play. We heat the inside of the building, but under the lanes it's much colder. Less heat means less friction, and ultimately, less hook. My Danger Zone doesn't seem to have lost any reaction that I can notice. In fact, sometimes I end up asking myself "why don't I just use this ball all the time?"