Thanks all for the responses.
I guess it is possible that 100+ tags COULD slow an SQL down, but to me it seems it would only be for a fraction of a second more as SQL initially checks tags based on where clause to see if indexes exist. I'm not sure about this but it seems logical that VFP would only do this ONCE before the SQL actually starts.
Rudy, I understand what you are saying too but seems like that has not much to do with indexes. I agree that it makes sense to break something like that into two SQLs instead of one but my question is really if someone was only doing one SQL say for that scenario would it really make a difference whether you only had a tag on FLAG and INVDATE and no others or whether you had 50 more indexes on other fields...
Just thinking out loud....