Carrier not getting Picked :Route/Zone

Hello Experts

I am using Route management in EWM and facing an issue.I am giving some carrier as Forwarding Agent in the OBD so that it flows along with the Outbound Delivery in EWM.

But in EWM the carrier is getting changed and my intended route is not getting picked.I have checked the ZONE and found that its of Mixed type and the customer is maintained in Zone-Location Tab but the corresponding Zip of the Customer is not maintained in Zone-Postal Code Tab alothough there are some other Zips available.

Does the Customer needs to be maintained in both the Tabs ( Location and Postal Code) for a Mixed Zone Pls clarifyif various parameters are used simultaneously in Zone how does System behaves.

Thanks

Akhil