Checking and freezing a payment batch

This is the part of a payment run that goes wrong quietly, so it is worth
five minutes before your first one.

Checking is a statement, not a click

When you check a batch, LEAT records a fingerprint of exactly what you
checked: which payments, in which order, to which accounts, for how much,
and the total.

That fingerprint is what makes the check mean something. A check with no
fingerprint is a person saying they looked at something, without saying
what.

Anything that changes afterwards voids your check

Add a payment, remove one, change an amount, change a bank account, and
the check no longer matches. The freeze will refuse and somebody has to
look at the batch again.

This is not the software being fussy. These are the three ways money
reaches the wrong place while every screen looks green:

• a payment added after the check, so the total signed for is not the total paid;
• an amount edited after the check, in one row out of eighty;
• a bank account changed after the check, which is how the right amount reaches the wrong person.

Freezing fixes the total

Freezing locks the list and the total together and produces a fingerprint
that gets printed on the sheet. That fingerprint is what the people at
the bank are signing against, even if they never look at it: it is what
lets anybody prove later that the sheet they signed is the sheet in the
system.

After the freeze, nothing on the batch can change. Not the amounts, not
the accounts, not who is on it.

Once a submission is recorded, the batch can never be voided

A frozen batch that has not gone anywhere can be voided, with a reason.
Its payments are cancelled and can be prepared again in a new batch.

Once somebody has recorded that it went to the bank, it can never be
voided. Somebody may be holding a signed cheque, and the record has to
keep saying so.

If the batch comes back unsigned, record that. Do not try to make it
disappear.

Payments are never moved between batches

If a batch is voided, its payments are cancelled where they are and new
ones are created in the new batch. Both records stay readable.

A payment moved between batches would be a payment whose history has a
hole in exactly the place an auditor would look.