Calculated Tables Advice

I'm pretty confident that there's a cleaner way but, working with what I see, I'd suggest exploring a solution along these lines:

Earlier Opening Opportunity Mon-Fri Count =
VAR Summary =
    FILTER (
        SUMMARIZECOLUMNS (
            DimShop[ShopKey],
            CurrentWeekTimes[Opening Time],
            DimTime[TimeSlot],
            TREATAS (
                { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday" },
                DimDate[DayNameShort]
            ),
            "@NetSalesExVAT", CALCULATE ( SUM ( FactSalesDetail[Net Sales Ex VAT] ) )
        ),
        DimTime[TimeSlot] = CurrentWeekTimes[Opening Time]
    )
VAR Grouped =
    GROUPBY (
        Summary,
        DimShop[ShopKey],
        "@ShopSales", SUMX ( CURRENTGROUP (), [@NetSalesExVAT] )
    )
RETURN
    COUNTROWS ( FILTER ( Grouped, ( [@ShopSales] / 5 ) > 40 ) )