Sorry for the link spam but it's a broad topic and the information you have provided is limited. Couple specific comments. First, I don't like VALUES. Second, is there any way you can limit the use of ALL and use ALLEXCEPT potentially or REMOVEFILTERS or KEEPFILTERS? I question the use of a SUMX within a CALCULATE statement, that seems redundant/unnecessary but hard to say.
Can you post sample source data and expected output?