Help for MMA in PIVOT table

Hi, The columns of my PIVOT table are as follows: month, quantity sum, and value. In order to compute the moving average every three months, I generate an additional normal table and populate each cell with monthly references. However, there are months in which there is no data in my PIVOT filter, which renders an alternative reference table for MMA inaccurate.

The inquiry at hand is:

1. May I include an additional calculated field in the PIVOT table that utilizes quantities to compute MMA for 3 months?

2: How can I modify the reference in my other table to ensure that the data remains accurate even in the absence of data for a given month?