This is a little hard to explain, but I will try my best.

On an invoice, Zen Cart (1.3.8a) displays the 'Total (inc)' price next to each product sold.

Here the VAT appears to be calculated on an individual item, rounded, then multiplied by the quantity. As far as I know this is the 'correct' way to do this.

But then underneath where the VAT total is shown, it is calculated based only on the subtotal (so not taking rounding into account!)

This means the VAT shown next to the products will not always add up to the VAT total on an invoice, when large product quantities are involved, it can become a big difference.

This appears to be a serious problem with Zen Cart's invoicing system.

I apologize if this is a known issue, but are there any plans for a fix?