Klarna Checkout issue

Hi,
I have noticed that the is a Bug in Klarna Checkout. It works okey untill you make any discout. Doesn't metter if general discount or with the code: Klarna popup doesn't show up when discount is activated. In Klarna Logs I could find this info:
{"error_code":"BAD_VALUE","error_messages":["Bad value: order_amount differs from the calculated value [1595] by more than [1]"],"correlation_id":"a86aefdb-cf66-4b95-8a34-bed7a3c7f4a1","service_version":"SNAPSHOT"} and it shows status 400. As soon as I remove the discout - it send and receive everything properly. Please take a closer look at this... I can tall you only ... that I have lost 2 Clients because they couldn't pay with Klarna :( Anyway, please if possible take a look at this. You can check it on www.schmucktapeten.de

thanks
Lukas