If certain items are to be taxed even when sold to an exempt customer, then you can enable this feature in the DynamicZip Setup window Item Categories with a Tax Option of Taxable and a Tax Schedule ID of ALWAYS TAXED (in the DZ Tax By Item Category Setup window will be taxed based on the line's tax schedule. If that tax schedule is a Zip Code Exempt Schedule then the related ZIP Code taxable schedule will be used in its place.
To Setup Always Taxed Items:
NOTE: If you have one or more customers who must be exempt, even on always taxed items, then you can use the always exempt option on the DZ Customer Supplement window.