The original DynamicZip Tax Reports were generated using native Dexterity code and local c-tree temporary tables. For a company with a lot of transactions, these reports could take an unacceptable length of time to generate. That is why we created SQL Optimized versions of the reports.
Although maintaining two versions is extra work, it has proven to be a great way for us to catch errors in the reports. The Non-Optimized reports also provide our customers with an alternative way to generate a needed report, should the SQL Optimized version fail for any reason.