Did you select the 41.6 gr - 41.7 gr as your node because of the lesser velocity spread over the 42.2 - 42.4 charge? I can see where firing a 3 shot group with these charges would be an advantage over firing just one shot of each charge. Had you not done that you could have easily selected 42.3 gr as you load without knowing the spread in velocity over the 3 rounds. There's not much difference in the two sets of groups in the 41.7 range and the 42.3 range.
This is a really interesting topic. I sure hope a lot of members look at it. It will likely give them new insight as to their "pet" loads if they are not aware of these methods.