Hi,
This issue happen because paypal don't round the prices like use.
We make the whole calcul and then round the final price, and Paypal don't seem to be doing it like that.
That's why this error happen and why we have added the option to not send the order details.
There is no really solution, but using this option.
This option don't change the way the orders are managed. When clicking on the payment button, it create the order in HikaShop even if it's not paid, etc. It's the normal behavior. It allow to have more statistics, or send email to customers who don't have finished their checkout...