Total # hrs work order spends with each department/time

Then add a Summary field for the Maximum Record ID # on the Work Order Change Table and use that to relate  the Work Order Change table to Work Orders.   You can now create Look Up fields in Work Orders from the Change Table



Now to move the Work Order to another Department you have the Users add a Record to the Work Order Change Table.   You might also use an Automation to create the record in the Change table based upon some criteria in the Work Orders Table.

The nice thing about this is you now know exactly when every child record was created and can look at the Duration between those records with additional Summary Fields in Work Orders on the Create Date.

Your users will also not be able to argue about the data the change happened.