I do have BJA3. It’s is a great book. Which part do you want me to read.
However, I have been using this formula to calculate my SCORE numbers:
SCORE = 10000 x (EV / SD)^2,
where EV is the 100-hand expected value and SD is the corresponding standard deviation. Clearly, the SCORE value is very volatile, because of the above quadratic formula. To compare the performances, it's better to use the EV-SD pair.
You write that you haven't fully grasped the definition of SCORE, and then you (accurately) write the definition!! I don't know how to respond to something like that. Why don't you reread pages 151-154, and then maybe we can put this (somewhat boring) conversation to bed.
Don