Using ALLEXCEPT with DATESBETWEEN - Don't understand scope of ALLEXCEPT

[apup]

Let's say I have a widget factory, and it produces different types of widgets. I would like a measure that returns the percentage of one type of widget produced against all types widgets produced. E.g. 

I have this formula

Widgets1Mth = DIVIDE(CALCULATE(COUNT(Widget[WidgetId]),DATESBETWEEN('Date'[Date],DATE(YEAR(TODAY()),MONTH(TODAY())-1,1),EOMONTH(TODAY(),-1))),CALCULATE(COUNTX(ALLEXCEPT(Widget,Widget[CreatedDate]),Widget[WidgetId]),DATESBETWEEN('Date'[Date],DATE(YEAR(TODAY()),MONTH(TODAY())-1,1),EOMONTH(TODAY(),-1))))

[v-ljerr-msft · Accepted solution]

Hi @apup,

Could you try using the formula below to create the measure to see if it works? 

Widgets1Mth =
VAR currentType =
    FIRSTNONBLANK ( Widget[Type], 1 )
RETURN
    DIVIDE (
        CALCULATE (
            COUNT ( Widget[WidgetId] ),
            FILTER (
                ALL ( 'Widget' ),
                Widget[CreatedDate]
                    >= DATE ( YEAR ( TODAY () ), MONTH ( TODAY () ) - 1, 1 )
                    && Widget[CreatedDate] <= EOMONTH ( TODAY (), -1 )
                    && Widget[Type] = currentType
            )
        ),
        CALCULATE (
            COUNT ( Widget[WidgetId] ),
            FILTER (
                ALL ( 'Widget' ),
                Widget[CreatedDate]
                    >= DATE ( YEAR ( TODAY () ), MONTH ( TODAY () ) - 1, 1 )
                    && Widget[CreatedDate] <= EOMONTH ( TODAY (), -1 )
            )
        )
    )

Regards