If an invoice is marked as paid in zistemo, it automatically removes the lines for “Amount Due” and “Paid Amount” from the totals block. If you want to keep this lines also on paid invoices (so the document will keep the same) you can enable it on the Settings/Preferences “Print also “Amount Due” on paid Invoices and Retainers”:
You can see the effect of this checkbox in the images below:
Checkbox “Show Amount Due” is not active:
Checkbox “Show Amount Due” is active:
