Can't use the plugin – generate false amount in adding

Did your plugin recognize “,” or “.” as decimal-point? Maybe this is the problem.

As the input fields are of type number both should work in a modern browser (like the current Firefox). The browser will handle all number format conversions before it is sending data to the server.
In Browsers incapable of numeric input fields you should enter a ‘.’ as decimal point.
If something goes wrong you should see it immediately after saving your settings.

OK. Thanks for information. In this case I have no idea why counting with a correct sum isn’t working.

The main problem is that woocommerce is not recalculating the taxes after the extra payment fee has been added.
Temporarily you can work around this if you set “includes taxes” to “no taxes”. This should at least yield a correct sum on the checkout page.

I am currently digging myself through the woocommerce code to see if I can provide a more profound fix.

Thanks for information but not possible.
So the tax-amount is wrong and so I’m producing with this fix the next problem.

Hopefully you’ll find a fix. In the meantime this issue produces false invoice and this is a MUST not happen issue.

I’m currently releasing v1.2.2, where this issue should be fixed.

working now. thanks a lot!