VeriFone VX 520 User Manual page 32

Note: If the final amount is 15% higher than the original amount, then a
pre-authorisation completion of the original amount must be done and the difference
done as a separate transaction
If the final amount is lower than the pre-authorised amount, complete the final amount,
and the balance will reverse
*The pre-authorisation completion must be done on the same POS device that was used
to pre-authorise
**Ensure the authorisation code is entered correctly as obtained from the bank; the POS
device cannot check the authorisation code, and if this code is incorrect, the amount will
not be paid into your bank account
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