Can we add sub-total columns based on other columns, but repeated (same type of calculation but based on addition of other columns)?

Hello, Jason!
 
Thank you for contacting us.
 
Kindly note that it is possible to create a calculated measure with a custom formula as follows:

measures: [{
          uniqueName: "Price",
          aggregation: "sum"
        },
        {
          uniqueName: "Discount",
          aggregation: "sum"
        },
        {
          uniqueName: "Calculated field",
          formula: "sum('Price')+sum('Discount')",
          caption: "Sum(Price+Discount)"
        }
]

We have prepared a JSFiddle example for illustration: https://jsfiddle.net/flexmonster/06db274r/.
You can read more about the calculated values in our docs: https://www.flexmonster.com/doc/calculated-values/.
 
There are also built-in Running Totals aggregations, which might be useful for your use case. You can read more about mentioned aggregations in the following article: https://www.flexmonster.com/blog/running-totals-in-pivot-grid/.
Please note that from 2.8.7 version of Flexmonster the Running totals aggregation described in the article is split into two different aggregations: Running Totals of Column and Running Totals of Row.
 
Hope you will find our answer helpful.
 
Kind regards,
Solomiia

Hello, Jason!

Hope you are doing well.

Our team is wondering if you had a chance to look through our previous response. Could you please let us know if the calculated values approach works for your case?

Looking forward to hearing from you.

Regards,
Solomiia

Hello, Jason!

Hope you are having a great week.

Just checking in to ask if the calculated values approach works well for your case.

Looking forward to hearing your feedback.

Kind regards,
Solomiia

Hello, Jason,

Thank you for the feedback.

We are glad to hear that it works for you. As always, you are welcome to reach out to us in case other questions arise.

Kind regards,
Nadia