VAT
VAT can be adjusted at settings 'VAT Types', but still you can change the VAT of an order line. To get a good overview about your periodical VAT: our reporting component has by default your periodical VAT report per quarter in numbers VAT low /high and also in a editable graph. All reports can be donwloaded.
This example shows that, if you change a VAT on a order line from 21% VAT to 1% VAT, it will show in the VAT total at the bottom creating a new group. The VAT settings and types will not be changed by this adjustment.