Shipping Charges getting divided down

Just wondering if anyone could tell me why my shipping charges (which are a flat fee) are getting divided by the number of suppliers in the order? eg shipping is $18, if someone orders from 2 suppliers in the same order the shipping is $9, if someone places an order from three suppliers, the shipping is $6.

Any help would be appreciated. Thanks.

Hello pdivi,

Thank you for your message. I am sorry to hear that you experience this problem.

The problem requires the investigation on your server. Please contact us via Customer Help Desk and provide us with a temporary access to your server.

Pavel Zyukin

CS-Cart Support team