You have a few options and routes to get the results you are looking for. The key that you are looking for is that if you have separate calculated fields, you can have different compute using configurations for each calculated field.
In the attached,
1. added two calculated fields:
Moving Average - Nested:
2. placed the Moving Average - Nested field on the Rows shelf.
3. from the pill's context menu, selected Edit Table Calculation
4. configured the compute using for Moving Average - Nested
5, changed the Calculated Field drop-down to Total, and configured its compute using
In Tableau, the pill that you select for compute using will be used for addressing, and all other dimension pills will be used for partitioning that calculation.
This was just a light walk through, I would be glad to explain in more detail if you contact me.