Hello Roxror, thanks for reaching out to us on the Community page, so you can alter the VAT amount whilst using a standard code, or you can create a custom one if you wish to. To alter the VAT amount on the invoice you need it to be set as exclusive of VAT for you to be able to edit the VAT amount once this is done and you have entered in say 100 pounds in amount> in the VAT box you selected 20%s then in the little total box for the vat you can alter the amount in there so to be 6.32 and then you will see in the total it will show you as 106.32 as the final amount for you.
