Based on ISO-22400-2
Actual Production Time (APT) divided by Planned Busy Time (PBT).
Planned Runtime per Item (PRI) multiplied by Produced Quantity (PQ), divided by Actual Production Time (APT).
Good Quantity (GQ) divided by Produced Quantity (PQ).
Mathematically, the variables cancel out and this simplifies directly to VOT / LT (Valued Operating Time divided by Loading Time).