custom aggregation in matrix not working

I have a matrix with 3 levels:

I have a custom aggregation, working fine, the dax code is:

FixedCosts = SUM('Table'[FCosts])

VariableCosts = SUM('Table'[VCosts]) 

Then create 2 measures:

Basic =
VAR _sumat = [FixedCosts] + [VariableCosts]
VAR _sumlevel2 =
    IF ( _sumat < 0, 0, _sumat )
RETURN
    IF (
        ISINSCOPE ( 'Table'[Level3] ),
        _sumat,
        IF ( ISINSCOPE ( 'Table'[Comp] ), _sumlevel2 )
    )

Result =
VAR _LEVEL1 =
    SUMX (
        SUMMARIZE (
            FILTER (
                ALL ( 'Table' ),
                'Table'[Proj] = MAX ( 'Table'[Proj] )
                    && 'Table'[Comp] IN VALUES ( 'Table'[Comp] )
            ),
            'Table'[Proj],
            'Table'[Comp]
        ),
        [Basic]
    )
RETURN
    IF ( ISINSCOPE ( 'Table'[Proj] ), _LEVEL1, [Basic] )

I want to add a higher level, that would just a simple SUM, but I am unable...

I tried re-writing the MEASURE as:

Result =
VAR _LEVEL1 =
    SUMX (
        SUMMARIZE (
            FILTER (
                ALL ( 'Table' ),
                'Table'[Proj] = MAX ( 'Table'[Proj] )
                    && 'Table'[Comp] IN VALUES ( 'Table'[Comp] )
            ),
            'Table'[Proj],
            'Table'[Comp]
        ),
        [Basic]
    )






VAR Higher_Level=
    SUMX (
        SUMMARIZE (
            FILTER (
                ALL ( 'Client' ),
                'Client'[Name] = MAX ( 'Client'[Name] )
                    && 'Table'[Proj] IN VALUES ( 'Table'[Proj] )
            ),
            'Client'[Name],
            'Table'[Proj]

        ),
        [Basic]
    )





RETURN
    IF ( ISINSCOPE ( 'Table'[Proj] ), _LEVEL1, [Basic] )
    IF ( ISINSCOPE (  'Client'[Name]), Higher_Level, [Basic] )

but of course in the ALL ('Client') I am forced to use only one table, so I am not sure how to do it..