SubProcess Smart Service - Set schedule based on processVariable in SubProcess

I have two processes:

Process A and Process B

Process A calls Process B using the SubProcess Smart Service.

When Process A starts it will have a target completion date for the entire process.

Process B is configured with a ProcessVariable that indicates a number of weeks prior to the target completion date that it should start (pv!startWeek). What I would like to do is set the scheduled start of the Subprocess Smart Service node based on that value like:

= a!subtractDateTime(startDateTime: pv!reset_date, days: pv!startWeek * 7)

My issue is that I'm currently not able to reference pv!startWeek from ProcessB from the Configuration of the SubProcess Smart Service in that calls it from ProcessA.  Is it possible to access this value in the configuration of the Smart Service?

Is there a better way to set this up?  I'd prefer to keep this config in the SubProcess Model as I wouldn't want to change all of my processes that call this SubProcess if we determine the schedule should be changed.  I know I could just configure a pv in the parent process or just hardcode it in the Subprocess Smart Service directly but would prefer to be able to change it in one place if possible.