Hi Jeeva,
Are you doing testing in your dev client or ides ?
SPRO- Plant Maintenance and Customer Service - Maintenance and Service Processing - Maintenance and Service Orders - Functions and Settings for Order Types - Create Default Value Profiles for External Procurement
This cost element looks like taken from IDES or copied system, you can change the cost element here, so it will not create any issues when you are creating the service.
Regards
Terence