general problems of the 2005 Audi TT

While driving down the freeway the transmission shifted to neutral and the car would not go back into drive. Fortunately the traffic was not heavy at this time and I was able to pull off the road without an accident. The neutral problem now occurs quite often and I now have the car in for repair. The transmission is a dsg automatic transmission and after reviewing information on the internet there have been a lot of problems with this transmission in all model years and Audi has only had a recall on later year vehicles with this transmission. I am not sure why the recall would not cover all earlier vehicles with this transmission as this is a serious safety issue and is also an expensive repair as the temperature sensing unit and the mechatronic unit have to be replaced and these were the items covered in the later model year recall. Please let me know why all defective transmissions are not covered.