This is purely speculation...but I have wondered if the V-boost opening late, is due to the COP being wired "backward"? On the 2 wire COPS you have a 12 volt ignition wire, and then a pulsed ground. So at 6000 rpm, each wire should pulse 1500 times a minute. (4 cylinders/ 6000 rpm).
On a car with a single coil, they would still run if you wired them up backward, but you wouldnt get the spark energy, and points would burn out quickly.
So....if the COP was wired up backward, and the Vboost couldnt "see" the pulses (rpms) for that cylinder....by the time that the Vboost could see the pules due to additional RPM that would put you at 7000-7500 (which is where some people will say that their Vboost comes in at after COPS were installed).
Again, purely speculation.