Description

1. The tax invoice template from KART-VN only allows one tax rate per invoice.
2. Therefore, we need to ensure that all service charges per tax invoice shall carry the same VAT tax rate.

Objectives

1. Enhance existing customer invoice module - add/edit pop-up to display a warning message when user groups service charges of different VAT tax rate into one invoice.
   The warning message shall warn the user that printing dot-matrix tax invoice is not available when tax rate is not the same.
2. In print dialog, disable the option to print tax invoice in dot-matrix when the invoice contains service charges with multiple tax rates.
3. This constraint only applies to tax invoices issued by KART-VN.

Estimation

16 hours, include development, developer testing, unit test development (if applicable) and peer test/review.