[Koha] Another report request -- Active Cardholders

There is a promising report on the Koha wiki (List Active Patrons by Category for a Specific Month). However, it doesn't seem to be providing valid results, even after changing "old_issues" to "issues". (The latter change produces counts in the single digits.) We're looking for a count of active borrowers between two dates, broken down by categorycode. ("Active" meaning at least one checkout between the two dates.) Appreciate any help! Cab Vinton, Director Sanbornton Public Library Sanbornton, NH