Paypal Express Checkout problem on 2.1.0.1

Hi,
after switching from Regular Paypal to Paypal Express Checkout i am facing a strange problem.

When a user has subscribed to the newsletter, a 5% discount is awarded on a new order.
When ordering (and on checkout page) all displays fine, with the 5% discount correctly substracted from the total.

Now when payment with Paypal Express Checkout is finalized and you are redirected to Paypal site, suddenly the total is not correct.
The discount is not substracted but added to the total.

Example:
On website during checkout
Item 1 = 100 eur
Newsletter discount = 5 eur
Total = 95 eur

After redirect to Paypal
total = 105 eur

This is a very big problem and hope that someone can help me with this.

thanks
Stefan