You want to count the no of values inside the multivalued field? Look for "mvcount" command available with eval.
Try using streamstats, like:
... your search ... | streamstats count(YourMultiValueField) window=1 global=f | ...rest of your search or report commands...
is it like this?
streamstats count(eval(status="passed"|sub_area="sub_areaA") window=1 global=f
??
or other format?