Auto Update a Pivot Table each Month

I have a pivot table which is designed to show current month 'forecast' vs 'actual' figures (see attached very simplistic sample).

Is there any way to get the pivot table to auto update on the eighth working day each month (M1 = April, M12 = March), rather than having to swap the 'Values' in the pivot table each month manually, so e.g. on the eighth working day of November columns C and D would auto update to display the 'forecast' vs 'actual' figures for November from the data set (without any manual intervention), or is this asking the impossible for Excel?

Many thanks