The way they explained it at Chrysler tech school was that if the normal production tolerances in the engine parts stacked in a way that the compression ratio was raised, then there might be pinging on regular. The reflash doesn't retard the timing, it just allows the interface with the DRB-III scan tool, which allows the timing to be retarded in 2* increments. If you have it reflashed, there are many other improvements possible in the programming. All of any applicable updates are included with the new program.

Chrysler uses knock sensors on other engines, the 4.7 v8, 5.7 Hemi V8, 3.5l and 3.8l V6s, and the turbo 2.4l come to mind.