Schema Design Inquiry In a timesheets data model, suppose I have an employee table, and a job table. Then, I also have an employeeInJob table to store an employee's rate for a given job e.g. 

employeeInJob (
    employeeId,
    jobId,
    rate,
    effectiveFrom )


A given employee may have multiple entries in the employeeInJob table for a given job since his/her rate may vary for that position over time. 

Now I have a timesheetEntry table:

timesheetEntry (
    employeeId,
    startTime,
    endTime,
    ???JobId )


My question is whether the timesheetEntry table should reference the job table or the employeeInJob table. I think having it point to the core job provides a more flexible design? Is this the case?
I think it's better that timesheetEntry table should reference to job table as

JobId will be PK of Job table and so associating timesheetEntry with job table will provide better referential integrity of data