general problems of the 2004 BMW 325

I purchased 4) 225/45/17 continental extreme dw tires. They were installed on my vehicle January 2013. The vehicle is a 2004 BMW 325 ci. It is garaged during the winter and was on the road from April 15, 2013 until November 15, 2013. It was not driven again until April 15, 2014. When the tires were removed to install new brake parts it was noticed that all 4 tires contain cracks in the the area between the tread, in large amount of area of the tire surface. With the tires off the wheels, the tire technician flexed the tire, as if to put a weight load on it, and the cracked opened up a noticeable amount. When I purchased the tires I was told that they were a top of the line model, and an upgrade to what was the oem tire when we purchased the vehicle new. There is no question that my tires have a defect. I paid the dealer tire depot 16 john Ave. Bristol, CT. 06010 $169. 00 to warranty the tires. My position is that the tires displayed the defects prior to my notice of them. They just didn't appear last week. I'm troubled by the fact that my wife has been driving on defective tires. I have obtain evidence that this defect is known to continental and is agent and or agents. At no point were we contacted of this defect by either continental or it's agents. Why I should pay any monies to replace tires that I purchased just over a year ago, and have been used far less than that time, is very disturbing to me. The decision to pro rate my defective tires based on remaining tread wear is also disturbing. With the tires being defective, than the performance and tread wear could be equally effected!.