Book stock is the opening dip stock plus receipts, less sales by the meters. Compare it with the closing dip stock. MDG 2024 allows a normal operational variation of 4% of tank stock, after considering evaporation and handling losses. A variation beyond that is an irregularity.
The method (Annexure 9)
| Line | Example, litres | |
|---|---|---|
| A | Stock as per opening dip | 9,200 |
| B | Plus receipts | 12,000 |
| C | Less shrinkage, where allowed | 0 |
| D | A + B − C | 21,200 |
| E | Less sales as per meter | 10,450 |
| F | Closing stock as per book | 10,750 |
| G | Closing stock as per dip | 10,690 |
| Variation, G − F | −60 | |
| Limit, ±4% of G | ±427.6 |
The variation is −60 litres, −0.56% of G. Within the limit. Try your own figures in the stock variation calculator.
What clause 5.1.11 adds
Stock reconciliation should establish any variation “after taking into account the normal operational variation of 4 % of tank stock and after considering” evaporation and handling losses for petrol and diesel, and shrinkage and temperature variation losses where those allowances apply. See evaporation loss allowance.
Beyond the limit
- Positive variation (gain): samples are drawn and sent to the laboratory, sales and supplies of all products stop at once, and the cause is studied.
- Negative variation (loss): samples are drawn; if the loss is beyond the limit, sales and supplies go on during the investigation, the dealer’s explanation is called for, and supply stops if it is not satisfactory.
Keep the inputs clean
Most stock variations are not theft or leaks but bad inputs: a misread dip, a meter reading copied wrong, test fuel counted as sales, or a receipt entered on the wrong day. Check those first.
Figures here are for reference. Your oil company’s certified calibration chart, approved instruments and the Marketing Discipline Guidelines always prevail.
Questions
Is 4% of the stock or of the sales?
Of the tank stock. Annexure 9 compares book stock F with dip stock G, plus or minus 4% of G.
Which is worse, a gain or a loss?
Both are treated seriously. A gain beyond the limit can mean product bought from elsewhere or something added, so sales stop and samples go to the lab. A loss beyond the limit calls for the dealer's explanation while sales go on.