Bank Account form, Bank Import Services page, Bank Account Import Service drilldown form, Import Batch page, Import Rule drilldown form, Transaction Value 'Not Applicable' not in dropdown

When a preconfigured Import Service is added with a default Import Rule, the 'Trans Value' may be set to 'Not Applicable' (depending on the service).
If you then drill down to the Import Service and then drill down to the Import Rule, the 'Trans' Value; is set to 'Not Applicable' but 'Not Applicable' was not appearing as a valid value in the dropdown list.