First, you haven't taken the advice given to you on your previous post, i.e., you have not used strictures and warnings. Also, it would be helpful to put data enclosed by code blocks.

I have a rough solution to your problem, but it doesn't show much since none of the data you've shown meet the criterion for keeping a summed pair. I'll post it (if no one else beats me to it) when I've cleaned it up a bit and added some new data.

Update: correct typos and grammar at code block.