dynamic Column header

Hello knimers,

I m working on a report in which i have to compare 2 periods against each other, and the name of these periods changes (at a time it can be month 5 and 4 and at a different time it can be month 5 and 6) which is why i renamed to p2 and to p1 to avoid keep writing and changing math formulas and rule engine every time. However, how can i revert to the old names.

I though of unpivoting then using string manipulation, but is there a better way?