I generally get lots of questions regarding this KR (knock retard) parameter and what it can mean. Aside from the obvious fact that the engine has encountered detonation and the ECU is pulling timing (and usually adding fuel depending on the tune), there are some nuances of KR that are not related to the timing values in the base tables. I made a post on my blog explaining some of these nuances and it is linked below. I have a slew of technical articles I want to put together (and have very little time) but here's a small start.
http://stratifiedauto.com/blog/knock...-kr-explained/