"A night auditor is the person who audits the hotel accounts daily at night or at a time when the business is relatively slow. The audit team generally comprises members of the accounts department. The number of people in the audit team depends upon the size, location, and products of the hotel. Since most of the activities of the night auditor are concentrated in the front office, the front office manager (FOM) may provide the necessary inputs for the night audit process. So the members of the night audit team generally report to the accounts department as well as the FOM. As a night auditor has to work in the night, the position doesn't find many takers, so most of the hotels do not have a permanent team of night auditors."
"A night auditor should be a skilled bookkeeper as he is required to track all the financial transactions between the hotel and its guests and to calculate the total revenue generated during the day. A night auditor should also possess the skills of a receptionist, as in many small and medium hotels, he may be required to carry out the check-in/ check-out function at night."
"Night auditors monitor the current status of guest accounts vis-à-vis the credit limits, and verify discounts, allowances, and promotional programmes that are offered to guests. They prepare reports about the front office operation for the management. Fully automated hotels may not require a team of night auditors as most of the functions (known as system updates) that a night auditor performs are carried out automatically by the computerised system, but a person is still required to physically verify the accounts and vouchers."
(Jatashankar R. Tewari in 'Hotel Front Office: Operations and management,' p. 303 OUP)