PrestaShop and PayPal payment error after checkout – 699 kr was paid instead of 699 kr [solved]

A client running PrestaShop 1.6.1.13 with PayPal payment module version 3.11.4 had problems after checkout of orders with an error message saying “699 kr was paid instead of 699 kr”. It turned out it was a rounding error where PrestaShop and PayPal use different methods of calculating the rounding.

The solution suggested was:

• Go to preferences -> General
• Rounding rule: Round to infinity when the value is halfway (recommended)
• Rounding Type: Rounding for each element

This solved part of the problem. However, the client applied a store wide discount of 30%, causing a product (for example) costing 999 kr to checkout at 699 kr. To be precise, 999 kr minus 30% discount is 699,30 kr, but the 0,30 was rounded off. The same problem as mentioned above occured even when putting one piece of this item in the cart and checking it out.

It turned out that the theme used (jms_homewares version 1.0) only display prices in full kronor, without any decimals, independent of the settings regarding decimals in the Preferences -> General tab. In this case the settings was set to display 2 decimals. Setting it to 0 decimals solved the problem. I should mention that I am not sure if this is standard behavoiur of jms_homewares or if it has been modfied by the website developer. However, in this case setting it to display 0 decimals made everyting work without errors.