Modify Maintenance Job Complete/Close date

We are just implementing the maintenance module and 1 request has come up.
With normal jobs, I can set the date the job closed so if I close the job a few days late, it can be changed. With maintenance jobs, I can’t see a way of doing this, and it is important for keeping the maintenance plans in sync with the actual date the work was performed.

Our main use case is when we have to send something for external calibration. We are going to use a maintenance plan, with a maintenance job to record the calibration as a subcontract operation. When we get the calibration certificate back, the date of the calibration will be different than the job closing date.

I’ve done a trace to see if I can get to the date with a BPM, but I can’t see that field in the trace, only the job closing field being updated. Any ideas on how I can set that date differently?
Mnt Job Close.xml (57.4 KB)