Advancing timing and retarding timing will not always affect your AFR's. Its true, your obviously seeing it as proof.
At idle my timing is about 17* and at cruising i am as high as 40* is some spots. Any timing over 35-36 really isnt makign any difference. The neon guys have tested to 54* and never noticed any difference in cruising ect.
Power tuning the timing map is something entirely different.
