Variance & Reconciliation¶

Wet-stock variance is the difference between the theoretical book stock and the physically measured stock. Tracking and minimising variance is a core operational objective.

Variance calculation¶

Variance = Physical dip reading − Book stock

Book stock = Opening stock + Deliveries − Sales

A negative variance (book > dip) indicates a loss — could be measurement error, evaporation, or actual product loss.

A positive variance (dip > book) usually indicates a measurement error or unrecorded transfer.

Variance report¶

The variance report shows:

• Opening stock (dip at start of period)
• Total deliveries
• Total sales (from nozzle totalizers)
• Closing book stock
• Closing dip reading
• Net variance (L and %)

Results are shown per tank, per site, and as a network total.

Acceptable variance¶

Industry norms suggest a wet-stock variance of less than ±0.5% of throughput is acceptable. Above ±0.5%, investigation is recommended. Above ±1.0%, escalation is required.

Variance alerts¶

Sites with variances above the configured threshold appear in the Back Office dashboard as amber or red. Investigate by:

1. Verifying delivery quantities against waybills
2. Checking nozzle totalizer readings for errors
3. Inspecting the dip chart and stick calibration
4. Reviewing pump test results for meter accuracy