Use counts and time that belong to the same observation
Record the start and end time, counter readings and physical counting point. Gross bottles and rejected bottles must refer to the same population. The formula used here is (total counted bottles − uniquely rejected bottles) × 60 ÷ elapsed minutes. Elapsed minutes include stops inside the observation window; this checker does not silently remove them.
- Identify the machine, installed format and bottle/cap drawing revisions.
- Retain the original counters or count sheets, not only the final rate.
- Do not subtract rejects again if the entered counter already reports only acceptable bottles; obtain a compatible gross count instead.