Monthly control checklist for e-invoicing companies

Two days before filing, the sales ledger has five fewer invoices than the point-of-sale system. Nobody knows whether they are rejections, contingency invoices that were never sent, or badly recorded voids. The accountant decides to “adjust” and files with an unexplained difference.

That problem is almost never born on filing day. It is born during the month, in controls nobody ran. Online e-invoicing automates issuing, but it does not replace control: what changes is that control can now be done with data instead of paper pads.

This is a monthly routine you can apply with spreadsheets or with whatever system you use. Legal deadlines and parameters are set by current regulations: confirm them with your accountant.

1. Reconcile issued invoices against registered ones

The goal is for three sources to agree: your invoicing system, the SIN’s (Bolivian tax authority) records and your accounting.

1. Export every invoice of the month from your system with its CUF and status.
2. Compare it with the status the SIN reports for those CUFs.
3. Compare the sales ledger total with the sales posted in accounting.
4. Explain every difference, one by one, before closing.

Suppose your system shows 2,000 invoices issued and the SIN has 1,995 validated. The reconciliation should end like this:

Item	Count
Issued in the system	2,000
Validated by the SIN	1,995
Difference to explain	5
In a contingency package not yet sent	3
Rejected, pending correction	2
Unexplained difference	0

If the last row is not zero, do not file until you know why. Check the reverse case too: an invoice the SIN has and your system does not (for example, a duplicate created by a retry). Those are the most dangerous, because nobody is watching them.

2. Review voids and credit-debit notes

Voids and notes are legitimate, but they are also the easiest path for errors and abuse.

• Every void has a reason and support. Who requested it, who approved it and why.
• Credit-debit notes are issued only against valid invoices. A note on a rejected or voided invoice has no basis.
• Voided invoices leave the ledger. Check that a voided invoice is not still adding up in the sales ledger, neither in the original month nor in the current one.
• Look for patterns. Many voids from the same register, the same user or right after closing deserve a question.

A useful indicator: void rate = voided invoices ÷ issued invoices × 100. If 40 of the 2,000 above were voided, the rate is 2%. What matters is not the absolute number but its trend by branch and by user.

3. Get operations ready for contingency

Contingency (when there is no connection to the SIN or the service fails) is solved in minutes only if it was prepared beforehand. Once a month, check:

• Each branch knows who declares contingency and how.
• The written procedure is visible to cashiers, not buried in an email.
• The paper pad or alternative method is available and controlled.
• No invoice packages from earlier contingencies remain unsent.
• The month’s significant events are recorded and closed.
• Manual invoices from the month, if any, have been transcribed.

If you want to see what happens step by step when the connection drops, we explain it in SIAT contingency: what happens when the internet goes down at your till.

4. Track code validity

Online invoicing depends on codes and credentials that expire: the CUIS of each point of sale, the daily CUFD, the digital signature certificate and the service access token. When one expires, the register stops invoicing.

Build a simple table and review it every month:

Item	Where it is used	Expires on	Owner	Next review
CUIS	Each point of sale
CUFD	Each point of sale, every day
Signature certificate	Whole company
Service token	Whole company
SIAT catalogs	Issuing	(synchronization)

The certificate and the token cause the most surprises, because they expire rarely and nobody remembers the procedure. Put the date in the owner’s calendar with enough lead time to renew them.

5. Review the sales and purchase ledgers before filing

Sales ledger:

1. The total matches the reconciliation in step 1.
2. No voided invoices are adding up.
3. The month’s credit-debit notes are reflected.
4. Contingency invoices landed in the right period.

Purchase ledger:

1. Each supplier invoice is valid and issued to your company.
2. There are no duplicates (same supplier, same number, same date).
3. Import DIMs are recorded with their taxable base.
4. The tax credit in the ledger matches the one posted in accounting.

Ledger-accounting difference = tax credit per ledger − tax credit per accounting. It must be zero or explained, item by item.

6. Define roles and owners

Control fails when “everyone” is responsible. A minimal split:

Task	Owner	Reviewer
Daily issuing and contingency at the branch	Cashier or branch lead	Branch manager
Follow-up of rejections and pending packages	Invoicing lead	Accountant
Approval of voids and notes	Branch manager or administration	Accountant
Validity of codes, certificate and token	IT or invoicing lead	Finance manager
Monthly reconciliation and ledgers	Accountant	Management

The essential point: whoever issues should not be the one approving their own voids.

Indicators to track month to month

• Validated on first submission = invoices validated without resending ÷ invoices issued × 100. If it drops, there is a data problem (tax IDs, catalogs, products).
• Unexplained difference in the reconciliation: must be zero.
• Pending contingency packages at close: should be zero.
• Rejection resolution time: days from rejection to a valid invoice.
• Void rate by branch and by user.

Common mistakes

• Reconciling only totals in bolivianos instead of invoice by invoice.
• Leaving contingency invoices “for later”.
• Finding out the certificate expired when the register can no longer issue.
• Fixing ledger differences without documenting their origin.
• Letting a single person issue, void and reconcile.

Moving it into a system

This routine can be done with exported spreadsheets, though it takes hours every month. An ERP like MKA reconciles each invoice’s status with the SIN, warns you before the CUIS and CUFD expire, handles contingency per branch with package submission and records each validated invoice in the sales ledger (see SIAT e-invoicing).