When creating an invoice through the API and passing the tax_code param, the invoice gets created but, the correct tax selection is not saved. Even stranger, is when you go to edit the invoice, in the UI, and the correct tax code show for a second, then switches to Zero Rated and removes the desired option completely. Trying this with HST, so the tax code in question is CA_HST_ON.
Any clue what this could be?
If using the tax_code param, you MUST pass the Ttx_amount and total_amount (which seems redundant). This appears on the invoice fine, however when editing the invoice, the same behaviour is experienced - the desired tax code disappears and Zero Rated is auto-selected. Is this an software glitch in the app? I assume this would only happen when created invoices through the API.