DAX formula Not working

Hi sixathur 
You're on the right track, and the issue likely stems from how measures work in Power BI. Since TOTAL VISITS is a measure, it dynamically evaluates based on the current filter context, which means you need to carefully control its aggregation to ensure only visits above 58 are counted.
try this
Extra_Visit_Cost =
SUMX(
VALUES('YourTable'[Week]), -- Iterate over each week
VAR VisitCount = [TOTAL VISITS] -- Get total visits for the current week
RETURN IF(VisitCount > 58, (VisitCount - 58) * 15, 0)
)

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