I have done some testing for you and I can understand your frustration. There is a particular process to get the lot code to set correctly based on LOTFROMCOMPONENT.
Cetec sets the lot code on an order at 2 points:
When you create the order
when a user clicks into the serial screen
So your process will be to pick the parts for the workorder, then immediately click into the serials screen. That will trigger the lot code being set on the order based off of the component lot code. You don’t need to set any serials, just the action of clicking into the serials screen will set it. After that, you can complete the order as usual.