I knocked it off and the outstanding balance hasn't changed

You received the money and applied it against the invoice. The settlement is listed. And the number you were watching has not moved.

Before you go looking for the payment — and that is where the afternoon goes — check which of three numbers you are watching. The AR and AP screens show three, side by side, and two of them are not supposed to move when you knock something off.

The 30-second check

Open the Outstanding Document Report and read the row’s three columns across:

Column	What it is	Does a knock-off move it?
ARAP Doc Open	What this document opened with, on its own — what it charged, less anything it collected at the moment it was raised	No. Never.
ARAP Contra	The total of everything that has since been applied against it	Yes. This is the one.
ARAP Balance	Doc Open plus Contra — what is still outstanding	Yes.

Now do the arithmetic. Doc Open + Contra should equal Balance, exactly.

It adds up, and Contra has moved. Your knock-off worked. You were reading Doc Open, which is a property of the document and is a constant for the life of it. Nothing is wrong.
It adds up, and Contra is still zero. The settlement did not reach this document. Open the document’s Contra tab and look — if there are no contra rows, nothing was applied here.
It does not add up. This is the real one, and it is rare. The settlement exists and the stored balance is stale. Skip to When it is a support matter.

What each number actually is

Doc Open is the document’s own face, and it is set once

When a document is created, BigLedger walks its lines and sorts them into two kinds:

the lines that charge — the goods, the services, the tax;
the lines that collect on the spot — the settlement methods, the cash and card taken at the counter as part of the same document.

Doc Open is those two added together. A cash bill that charged RM 2,400 and took RM 2,400 in card at the till opens at zero and is finished the moment it is raised. An invoice that charged RM 2,400 on credit and collected nothing opens at RM 2,400.

It is recalculated whenever the document itself changes, and at no other time. No part of the settlement machinery ever writes to it. So if you are watching Doc Open for a payment to land, you will watch for ever, and correctly.

That distinction has a practical edge worth knowing, because “knock off” is used in the business for both of them:

You took the money…	It is recorded as	It shows up in
on the document itself, at the counter	a settlement line on the document	Doc Open — the document opens already reduced
afterwards, against an existing invoice	a contra between two documents	Contra, and therefore Balance

Two different mechanisms, one everyday word. Most “the balance did not change” questions are this sentence.

Contra is a mirrored pair, not an entry

A settlement between two documents is stored as two rows, linked as a pair: one filed against the invoice, one against the receipt, with the amount negated on the second so each document sees the movement from its own side. That is why both documents’ balances move from one action, and why you will find the same settlement listed on the Contra tab of each.

The document’s Contra figure is then re-summed from those rows — every active contra it takes part in, added up again from scratch. It is not nudged up and down. That matters for the one failure mode on this page: because it is a re-sum, a single missed refresh does not corrupt anything permanently. The next settlement against the same document recomputes the whole figure and puts it right.

Balance is simply the two added together

Balance = Doc Open + Contra. There is nothing else in it. Every “as of today” report — Outstanding Document, Aging, Statement of Account — reads this figure straight off the document, live. It is not a snapshot and it does not go stale with age.

(The historical aging reports are a different matter entirely, and that is the next page along.)

Three ordinary reasons Contra reads lower than you expected

The amount rounded to nothing. Settlement amounts are rounded to two decimal places before anything is written, and a row that rounds to exactly zero is dropped silently. A one-sen residual you tried to clear this way simply is not there.

You settled a different document. The invoice and the receipt each have their own Contra tab. If you cannot find the pair on the invoice, look at the receipt — it will name the document it was actually applied to.

Somebody unwound it. Voiding the receipt deletes the contras and recomputes both documents’ balances, so an invoice goes back to outstanding. That is the void working — see What a void undoes.

When it is a support matter

The signature is arithmetic: Doc Open plus Contra does not equal Balance. If the Contra tab lists settlements that the Balance has not absorbed, the rows were written and the header was not refreshed. Report it in those words, with both figures and the document number.

Here is why it happens, so you can recognise the shape rather than guess at it.

When a settlement is created, the contra rows are written and then each affected document’s balance is recomputed inside the same call — there is no queue and no delay, which is why a knock-off normally shows on the screen the instant you save it. But the two ways of creating one behave differently when that recomputation fails:

Settling several documents in one go treats a failed recomputation as a failure of the whole operation. It stops, and nothing is written. You get an error, which is unwelcome and honest.
Settling a single document logs the failure and carries on. The contra rows are committed and the header keeps the balance it had. Nothing on your screen says so, and nothing sweeps it up afterwards — there is no watchdog that re-selects documents whose balance disagrees with their contra rows.

Voiding a settlement behaves the same way as the single path.

Because the figure is a re-sum rather than a running total, the damage does not compound, and the next settlement against the same document will correct it by itself. If the document is finished and no further settlement is coming, it needs a correction — the customer’s own word for it is a data fix — and that is a request, not a button.

What this page cannot tell you

Whether your tenant has a stale row right now. Nothing in the product lists documents whose balance and contras disagree. The arithmetic above is the only check available from a screen, and it works one document at a time.
How to unwind part of a settlement from a screen. Reducing a contra without removing it exists as an API operation, gated on an administrator permission, with no screen behind it. From a screen the choice is to leave it or void it.
Why the historical aging still shows the document. That is a different stored figure with a different refresh rule — the aging still shows an invoice that’s already paid. A back-dated settlement does trigger a rebuild of the months it affects, but only on the settle-several-at-once path.
Whether the underlying amount is right. All this tells you is which of the three numbers you are reading and whether they agree with each other.