An invoice audit is a comparison, not an investigation. Knowing what it can and cannot show keeps the result useful.
Verification
- Verified as at:
- Source:
- Omnium method; validation is performed against the signed contract
- Last reviewed by:
- Omnium
Figures in this sheet were current at the verification date above. Regulated charges reset each April. If you are relying on a figure, check the source or ask us.
A4 board pack. Cover page, then a running head and foot on every page.
What an audit actually is
An invoice audit is a comparison, not an investigation. Each line on the invoice is read against the signed contract for the period billed, and the arithmetic is recalculated rather than accepted. Where the charge depends on a figure held elsewhere, such as the agreed capacity for the supply or a meter reading, that figure is checked too.
That is the whole method. It is unglamorous, and it is why the errors it finds tend to be small, repeated and long-standing rather than dramatic.
What it can find
| Tested | Evidence needed |
|---|---|
| Rates and standing charges | The signed contract, including price change dates. |
| Availability and reactive charges | The capacity recorded for the supply, and half-hourly demand data where it exists. |
| Readings and estimates | The reading history for the meter, so a run of estimates can be seen as a run. |
| Meter and site ownership | Your list of supply numbers and occupancy dates for each site. |
| Taxes, levies and reliefs | The nature of the site and any relief declaration already in place. |
What it cannot find
An audit cannot find an error the invoices and the contract do not show. Where the only record sits with the supplier or the network operator, it has to be requested, and that takes as long as they take.
It cannot tell you whether the rate you signed was competitive on the day you signed it. That is a procurement question, answered by testing the market at renewal, not by reading a bill.
It cannot recover money outside the period a supplier will reopen, and that period differs by supplier, by charge type and by the reason for the error.
It cannot make correctly billed consumption disappear. Plant running through closed hours is a real cost, correctly charged. Reducing it is separate work with its own costs and payback.
When the answer is that nothing is wrong
Some accounts are billed correctly. Where that is what the read shows, that is what we report. A clean result is a useful result: it tells you the billing is not where your cost is, and points the work at consumption or at the next renewal instead.
Where data is missing, the gap is recorded as a gap. We do not estimate around a missing reading to make an invoice reconcile, because an invoice that has been made to balance is not the same as an invoice that has been checked.
Related sheets
- Invoice validation
What goes wrong on energy invoices, how validation works against the contract, and why we validate for payment rather than approve.
- Recovering an overcharge from a supplier
How a billing query is raised with an energy or water supplier, the evidence it needs, how far back a claim can reach, and what a recovery looks like.
- Reading your energy bill
What every line on a commercial gas and electricity bill means, so you can check it is right and see which parts you can influence.
Take this sheet into a meeting
What an invoice audit finds, and what it cannot exports as an A4 board pack: a cover page carrying the title and the verification date, then the sheet itself with a running head and foot on every page.
If this sheet raises a question about your own sites, speak to us.