Supplier vs. Customer Total in Matrix Visual for Power BI

[SDittmannFleet]

I have a matrix with "Supplier" and "Customer" in the row fields, the latter being nested underneath "Supplier". I want to include a column, "Rejected Expense". If I simply do an aggregated field, it lists the "Supplier" total and repeats it for all of the customers underneath it.

I wrote a measure to change this, but it doesn't give me a correct "Supplier" total. Basically, the expected outcome is:

• If there is a value for at least one customer row, return the sum of all customer rows as the supplier total.
• If there are no customer row values, return blank.

However, that is not what is happening. It takes the LAST customer value and returns it as the supplier total:

This is the measure as I have it to-date:

Rejected Expense = 
VAR Cust_total =
    CALCULATE (
        SUM ( Rejections[Grand_Total__c] ),
        MAXX ('Price Schedule', 'Price Schedule'[Customer Account ID] ) = 'Rejections'[Customer_Branch__c]
    )

VAR Supp_total =
    CALCULATE (
            SUM ( Rejections[Grand_Total__c] ),
            MAXX ('Price Schedule', 'Price Schedule'[Supplier Account ID] ) = 'Rejections'[Supplier_Account__c]
        )

RETURN
    IF (
        ISFILTERED( 'Price Schedule'[Supplier Account ID] ),
        Supp_total,  // if current row is supplier row, return supplier total
        IF (
            ISBLANK( Cust_total ),
            BLANK(),    // if no customer total, return blank
            Cust_total // else return customer total
        )
    )

This is the data model:

I found a video online where he works with a virtual table and forces the totals to show up correctly here, but I couldn't even get it to produce said table in DAX Studio, so no luck there. I know totals/subtotals in a matrix can be finicky, but there HAS to be a way to do it.

Any pointers would be greatly appreciated!

[SDittmannFleet]

Update: it appears that the measure picks the LARGEST value, but only if there are contiguous items underneath the supplier line?!