Welcome Erwin to this board,
The groupwhere you placed your question is Performance and Tuning. The performance in this group is the performance of the application, so I think your question can better be asked in another group. Most likely the group
Manufacturing & Supply Chain
is the best group to post your question.
You can also Search
on keywords like WIP.
Sorry I can't answer your your question, but hopefully you can do something with this.