The short answer
Review i.SAF at three levels: file validity, invoice records and consistency with the accounting evidence. Investigate duplicates, missing entries and unexplained differences rather than treating successful validation as final approval. Keep the reviewed version, submission result and any correction decision together.
Separate three kinds of check
Technical validation asks whether the file meets the required structure. Record review asks whether the invoice details are accurate. Accounting review asks whether the treatment reflects the transaction. Assign all three; do not assume the person who presses Export has completed them.
Use the current VMI i.SAF submission and correction guidance, checked on 6 October 2026, for the authority's process. The checks below are a proposed firm's review routine, not a list of every VMI validation rule.
Start with identity, dates and duplicates
Record review worksheet
| Check | Test | Action |
|---|---|---|
| Reporting period | Does the export cover the intended period? | Confirm source dates and export filters |
| Counterparty | Does the record match the original invoice? | Correct the source record, not only the export |
| Invoice number | Is the identifier accurate and consistent? | Compare with the document |
| Possible duplicate | Same supplier, number, date and amount? | Investigate before deleting |
| Credit note | Is the document type and sign treatment correct? | Link to the original and obtain review |
| VAT classification | Does the code reflect the actual transaction? | Have the accountant confirm the treatment |
A duplicate check should produce candidates, not automatic deletion. Two suppliers can use the same invoice number; one supplier can issue several documents with similar amounts. Keep the supplier identifier in the test and compare the original documents. Record the decision so the same item does not reappear as an unexplained exception.
Reconcile totals to the accounting records
Compare invoice counts, net amounts and VAT amounts with the relevant accounting exports. Investigate differences by category: omitted document, duplicate, credit note, timing or classification. A report with correct totals can still hide two opposing errors, so combine total checks with exception review.
Suppose the register total agrees with the ledger, but one invoice for €500 was duplicated and a different €500 invoice was omitted. The zero difference is not proof of completeness. A document-level count and supplier-level review expose what the total hides. The amounts here illustrate the control; they are not tax calculations.
Do not force the VAT return to fit
VMI has separate FR0600 assessment guidance, checked on 6 October 2026. Differences may need correction or explanation, depending on their cause. Keep a reconciliation note rather than adjusting the return solely to remove a warning.
When an authority message arrives, record its exact requested action and response date. Assign a reviewer to decide which record requires correction. Do not presume both the register and return must be resubmitted in every case. Link the final response to the original period.
Use a short release checklist
Before marking i.SAF complete
Before marking i.SAF complete
- Client and period confirmed; source data version recorded.
- Export passed the applicable technical checks.
- Duplicate candidates and missing-document exceptions resolved or explained.
- Relevant totals reconciled and tax classifications reviewed.
- Final submission status checked in the authority's system.
- Acknowledgement, reviewer and any follow-up recorded.
Keep fixes in the accounting source wherever appropriate. Editing only an exported file creates a different version that the next export can overwrite. Use the monthly VAT workflow to place this review before submission and the bank-statement process to identify missing evidence.
Questions
No. It can help with file structure and selected rules, but it cannot establish that every transaction was recorded or that its accounting treatment is correct.
No. Offsetting errors can leave the total unchanged. Review records and exception lists as well as amounts.
About this article
Author: Claister
Published by Claister, the company building the accounting practice management software discussed on this website.
Design partner: Natalija Miadzelic
Tax review: Natalija Miadzelic · Accountant · Approved
Consulting an official source is separate from a qualified review of how a rule applies to a particular client.
Editorial policySources cited in this article
- VMI i.SAF submission and correction guidancePage consulted ·
- FR0600 assessment guidancePage consulted ·
Dates below describe recorded source consultation, not professional approval. Sources without a recorded date are listed without one.
Accounting processes: monthly work to annual accounts
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