What you process does is bring ALL of your records into Context and then change all of the values to the value of one arbitrary record. AIM can't build edit multiple records to multiple different values.
If you want to make each individual record be modified then you need to pass these to a second process individually.
Process 1
Process
Find ALL LabourReviewAllocation
UpdateRecords
Process 2: UpdateRecprds
Input LabourReviewAllocation
LabourReviewAllocation.AllocatedHoursWeek0 = LabourReviewAllocation.AllocatedHoursWeek1
LabourReviewAllocation.AllocatedHoursWeek1= LabourReviewAllocation.AllocatedHoursWeek2
LabourReviewAllocation.AllocatedHoursWeek2 = 0
This second process will receive exactly one record process the updates then cycle through the next record until all of the records from the FIND are completed, before moving on to any subsequent processes.
The process you used originally is good for instance when you want to change all of the records to one value, for example changing all of the Accounts in a system to have a new SalesAssociate.