And it DOES look like the simple rule to model this is:
The amount of charge a coupling capacitor C22 is able to remove from the first capacitor C21 follows C22/(C21+C22) so never 0 but never 1.
But its not too bad as obviously V ~ Q and E ~ V^2 so removing half the charge means energy wise the integral between 0.5 and 1 over 0.5*X^2 from the total energy that is gotten by integration starting at 0 is removed.
So for those example values thats 88% being removed.