You need to optimize buffer size, setup time, batch size, product variants, etc. You need to communicate your ideas about a change of a production system or a new system. Simulation skills are scarce and expensive. Possibly, you may need to purchase this skill instead of simulating by yourself if you cannot find the necessary time to build up this skill within your own premises, especially with regards to the complexity of using ordinary simulation packages which cannot be adapted to your domain of activity. Quality products are not always available.
Startup cost is too high.
The system is based on resources called elements, which can be viewed as a Petri Net or as a queueing network. The transitions in the elements always occur as soon as possible, with a very sophisticated technique determining which event is to be fired when more than one event may occur at the same time. The software is fully portable under several operating systems, which only modifies the look and feel of the user interface by adapting it to the operating system.