How to use a "measured column" to filter a virtual table

[ImSctm]

Hello,

Does someone know how to filter a table from a created column that comes from a new variable? I'll show the measure:

--------------------------------------------------------------------------------------

VAR Dif_Hours =

Hores_Mes_Actual - Hores_Mes_Anterior

//I have a number diference = [hours this month - hours previous month] as a starting point //

VAR Numero_Feines_Incrementen =

    COUNTAX(

        CALCULATETABLE(

            ADDCOLUMNS(

                SUMMARIZE('Productivitat DIA','Productivitat DIA'[NAME]

                ),

                "Dif_Hours123",Dif_Hours

            ),

        Dif_Hours123>0),

    'Productivitat DIA'[NAME]

    )

//What I want is to use the variable Dif_Hours as a filter to COUNTAX and only count rows number of Productivitat DIA'[NAME] that have Dif_Hours > 0.  //

Of course, DAX doesn't accept the new column "Dif_Hours123" as a table name or a correct function. But I can't find a suitable alternative.

Much appreciated if you can help...


Update: 
I've got something closer by applying countax after virtual table. Still result not satisfactory as it shows total of rows without filter:
Total is 11 and by filtering it should be 5.

----------------------------------------------------------
VAR Diferencia_Hores =

Hores_Mes_Actual - Hores_Mes_Anterior

VAR Taula_Dif_Hores =

    CALCULATETABLE(

        ADDCOLUMNS(

            SUMMARIZE('Productivitat DIA','Productivitat DIA'[NAME]

            ),

            "Dif_Hores",Diferencia_Hores

        )

    )

RETURN

COUNTAX(

    FILTER(Taula_Dif_Hores,[Dif_Hores]>0),[Dif_Hores])