This paper analyzes a problem of optimal inspection intervals for a failure-prone batch production facility. The model makes a seemingly minor modification to similar models that have appeared recently, but which results in a significant change in the form of the optimal policy. Optimal solutions are developed for both continuous and integer valued sublot sizes. The paper also examines the effects of inspection sublots in an economic lot sizing context and shows that a simple, exact modification of the Economic Production Quantity formula is often possible in the continuous relaxation of the problem.