A Lookup-Number type attribute is mapped to a Number field under MSP Field Mappings in CAPPM. When the schedule is opened in MSP the value of the attribute is not displayed even though the tasks have a value for this attribute and instead all values are shown as zero.
The document below states that all Number type attributes should be mapped to Number fields in MSP:
MSP Mapping Documentation
However, for Static Lookup -Number type attributes Text4 to Text30 fields should be used else the above issue occurs.