Not all downtime is equal, and lumping it together hides the number that actually matters. Planned downtime — a scheduled PM, a changeover — is budgeted for and doesn't hurt throughput forecasts. Unplanned downtime is the figure worth tracking obsessively, because it's the one nobody scheduled around.
For automated lines specifically, unplanned downtime carries an outsized cost: a stopped shuttle or a jammed conveyor zone on a single-stream system can cascade into missed truck cut-offs at a cost measured in hundreds of pounds per minute, not just the value of the idle asset itself.