[.041 Safety Wire]

I believe that chart is showing you that all the rounds are set to converge at a single point in space plus the convergence and divergence in inches with regard to setting them at 250 yds as opposed to 350 yds. All rounds should converge at a single point so when your target is in the sweet spot you can get as many rounds in it as possible. To set pairs at different convergence points would lower the overall effectiveness of your weapons system.