The cost of any simulation or model is directly related to the time/energy put into it - and the desired accuracy of the output. It's also related - in power distribution systems - to the SIZE of the system being modeled/simulated and the number of case simulations required. The larger the system, the higher the amount of effort involved ... and the higher the final cost.
If the model builders /simulators are required to "walk the facility" to get the data for a large project, the cost can be higher than if the owner/operator does the legwork themselves. Passing complete data along in a timely fashion helps keep the price down, too.
Converting energy to motion for more than half a century