Additional Worker/Helper in Job Card

Hi All,
I have a situation where in a Job Card/Workstation there can be more than 1 employee (fluctuates depends on available personnel), for example for packaging, where the company hire freelance helper to help packaging. How to do it so that the number of additional worker hired can be put into Production cost to its related finished good/item ?

  1. I thought making item with un-checked maintain stock as a service, but where to put it?
  2. another idea, is to put into additional cost in Work Order but again after submitted, additional cost is not editable, ideally (I think) after all job cards are finish, then the system can collect hours of helper into additional cost in WO at finishing WO.
  3. If I put on Stock entry additional Cost, first the cost is not as material transfer as its nature, so it’s kind of wrong way.