I have performed test with ENTITY-type dimension BE (created DATA property 8 characters).
One base member has property set to 20040101, other base and parent members - 99991231
The formula was:
=EPMDimensionOverride("000";"BE";"DATA>20140101;BAS(FPBE)")
The result - 6 base members!
Without DATA check:
=EPMDimensionOverride("000";"BE";"BAS(FPBE)")
Result - 7 base members!
Vadim