Average Score over time with non-contiguous dates

richhthfc Came up with this:

Measure = 
    VAR __MonthNo = MAX( 'ClientScoresOverTime2'[MonthNo] )
    VAR __Clients = DISTINCT( ALL('ClientScoresOverTime2'[ClientName]) )
    VAR __Months = DISTINCT( ALL( 'ClientScoresOverTime2'[MonthNo]) )
    VAR __Table = SELECTCOLUMNS( CROSSJOIN( __Clients, __Months ), "__ClientName", [ClientName], "__MonthNo", [MonthNo] )
    VAR __Table1 = ADDCOLUMNS( __Table, "__Value", MAXX( FILTER( ClientScoresOverTime2, [ClientName] = [__ClientName] && [MonthNo] = [__MonthNo] ), [Score] ) )
    VAR __Table2 = 
        ADDCOLUMNS(
            __Table1,
            "__Value2",
                IF( 
                    [__Value] <> BLANK(), 
                    [__Value], 
                    SUMX( FILTER( ALL('ClientScoresOverTime2'), [ClientName] = [__ClientName] && [MonthNo] = [__MonthNo] - 1 ), [Score])
                )
        )
    VAR __Table3 = FILTER( __Table2, [__MonthNo] = __MonthNo )
    VAR __Result = AVERAGEX( __Table3, [__Value2] )
RETURN
    __Result