Over time, LC has added several fields, such as "inquiries in last 12 months". In such fields, most loans have no data. NSR treats no data as if it were zero. This results in misleading back test results. I believe many users do not realize that they are entering filters where some loans have no data for a particular field.
I suggest you treat no data as different from zero, and report it on a separate line in the breakouts. Also would be good to allow the user to specify how to filter no data. For example, whether no data should pass or fail the filter.