XI is probably far improved over version 9.   I've been pulling my hair out messing with it in my current contract.   Pain in the tookus.

What does your query look like now?

Nope.   You'll need the cascading parameter set up.  SSRS doesn't hold the query results somewhere, and thus has nowhere it can go but back to the server to get them,...

Are you sure that the filters are coded for = as opposed to <> ?

This may be a matter of understanding the data in your dataset, and possibly modifying that query to bring the needed data forward into the report so that you can...

You could write a SELECT that puts each query in a set of parentheses, and then has the divide symbol (/) between them and an AS RESULT afterwards.   Potential problem...