If external pricing is applicable for the Network and Source in Source Network Preferences (PMDSORNW), system performs the following additional validations:

• If the customer record is found in External Pricing System Customer Preferences (Function ID: PMDEPCST) and if the customer is allowed for external pricing, system generates the external pricing request. If the customer is disallowed, internal pricing is applied.
• If the customer record is not found in External Pricing System Customer Preferences (Function ID: PMDEPCST), second level check is done with External Pricing System Customer Service Model Preferences (Function ID: PMDEPCSM).

If the service Model is allowed, system generates the external pricing request. If the CSM is disallowed, internal pricing is applied.

• If CSM level maintenance is 'Allowed' and no CSM listed in the multi block, it indicates that all CSMs are disallowed. For this case, in the second level check for CSM, external pricing is not applicable for the transaction, internal rates are applied.

If CSM level maintenance is 'Disallowed' and no CSM listed in the multi block, it indicates that all CSMs are allowed. So if the customer level record is not found and CSM level is maintained as 'Disallowed' with no CSM listed, then external pricing is applicable for the transaction.