Workload Control (WLC) has been developed as a production planning and control approach for make-to-order manufacturing. Previous studies on WLC often assume a simplified shop where released batches are treated as independent jobs, which proceed through the different stages of processing without being split. Batch splitting allows released batches to be split into a number of smaller sub-batches so that its operations at work centres can be overlapped and its progress accelerated. This paper investigates how WLC performs under batch splitting. Evaluating the performance of WLC in this context is an important step towards the alignment between WLC theory and practice. Thus, assuming a production situation with unbalanced utilizations of manufacturing resources, the effectiveness of different dispatching rules and job release strategies are examined using simulation. Results highlight the importance of controlled release of jobs to the shop floor and the importance of differentiating between bottleneck and non-bottleneck work centres for purpose of dispatching.