Keep invoice amount remaining while WTH is correctly calculated 10% and no deduction is recorded

The purpose of this case is that vendors are mainly from overseas, they don't have any obligation to pay WHT which is completely paid to Malaysia government by a company. Expectation from the system is not change the total amount of the invoice. For example for RM1,000 invoice amount payable to external vendor), withholding tax rate is 10% and tax payable to our government (not vendor) is RM100. When user try to apply 0% nondeductible, the withholding tax amount is RM100 (which is correctly calculated). Therefore the vendor invoice amount will keep by the system to RM1000.