My understanding are:
1. The maintenance jobs like Replacing, repairing or PM (Preventative Maintenance) work order “use Maintenance Cost code”
2. The jobs for Installation or Extension that request by MCD/contactors “use Contactors cost code (back charge cost code) or Project cost centre if the Project jobs”.
The Cost code is existed on work order below is : 610001- Maintenance – Workshop and done by PZC not MCD.