DAX Calculation Issue from granular table to summary level DAX Statement

Hi, KarenFingerhut 

I just got this thread today. It's easy to make mistakes with time-intelligence functions so it is not recommended.

Since you are using slicer, we need to build a context in the card.

Like this:

# Flag Spend > 300 Per Month =
COUNTX (
    SUMMARIZE (
        Fuel,
        [InvoiceDate],
        [operative_name],
        "sum", IF ( SUM ( Fuel[GrossValue] ) > 300, 1, 0 )
    ),
    [sum]
)

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If not, please feel free to ask me.

Best Regards,

Community Support Team _Janey