Interesting. I've never heard of that. My MSD Digital 6 box never retards the timing, but I only rev to 7000 rpm. It starts at 35* and hits the rev limiter at 35*. It does have the capability for things like N02 and a High Speed switch retard etc. Is that what you mean?
Prior to locking out my MSD, I had 22 initial and the rest of the mechanical to reach 35* was all in by 2000 rpm. I never really drive with the motor below 2000 rpm though, and certainly never fully load it below 3000 rpm.