Pete:

The DTOC() function has a ",1" argument that creates a string as YYYYMMDD.

How's this;
1.) Create an index tag with this format;
INDEX ON DTOC(CTOD(serv_date),1) TAG serv_date_YYYYMMDD

2.) Then, format the field accordingly so you can find it (or FOR clause it) quickly;
m.serv_date = DTOC(CTOD(serv_date)),1)

You could then use the m.serv_date var for lookups, comparisons, etc. and get the Rushmore speed you need.

HTH
Bill