Paypal not adding shipping for additional products

I have this code for a product:
[wp_cart_button name="Actual product here" price="295.00" shipping="19.95"]
And this code for another:
[wp_cart_button name="Actual product here" price="119.00" shipping="7.00"]
In the cart it shows:
Subtotal:414.00
Shipping:26.96
Total:440.95
At PayPal checkout it shows:
Item total 414.00
But when calculating shipping it only shows 19.95 and doesn’t add the 7.00.
Two other products have 7.00 shipping entered in the code.
When I enter one in the cart and checkout at PayPal it shows the correct price and the correct 7.00 shipping.
When I put both products in the cart and checkout at PayPal the price total is correct but shipping shows 19.95 instead of 14.00!
What am I missing?

http://wordpress.org/plugins/wordpress-simple-paypal-shopping-cart/