Create an extrapolated version

Hi community,

I am performing a Data Action to create a new version. Imagine that I only have real data until August and I want to create a new version that until August contains the real data and from September it contains the average of the real data. That is, I would have to calculate the total amount that was until August and divide it by 8 and that is the amount that will go in the remaining months. I am having problems when creating this data action and I would appreciate a little help.