NIAGARA FALLS – A state audit of student enrollment and billing at Niagara Charter School for the 2012-13 fiscal year has found that billings and enrollment figures were not always accurate, State Comptroller Thomas P. DiNapoli reported Thursday.

Auditors said that a number of students who attended for less than the entire year were counted as full-time, resulting in more than $10,200 in overbilling of the students’ home school districts. In a sample of 52 student billings, auditors said they found errors on six of them.

Auditors also noted that in a review of 22 student residencies, upon which billing is based, five of them did not have sufficient proof of where they lived.

In response, James C. Muffoletto, president of the school’s board of trustees, wrote that the enrollment discrepancy was a one-time incident, that policies to confirm addresses are in place and that billing and year-end reconciliation will be done in a more timely manner in the future.