Form Design(Spliting the column in Act and Fcst with dynamically change of the period)

Summary:

A basic type of requirements(I guess).

We have a requirement to redesign one of the form and to split the periods in column to have different combination of actual and different combination of forecast. Somewhat like this.

The challenge is to have the periods rolling every month for actual and forecast dynamically. I am able to think of few options:

1. Using variable to update every month. Not an ideal solution.
2. Currently, the period dimension is not a flat structure so, I am not able to use Lsibling/Rsibling function. Don’t want to create an alternate period hierarchy just for the form.