COLUMBUS, Ohio — Enrollment at Ohio’s largest online charter school is nearly 60 percent lower than originally reported, potentially jeopardizing about $60 million of the e-school’s state funding from last year, a state education official says in a letter released Monday.

The Ohio Department of Education has given the Electronic Classroom of Tomorrow 10 business days to appeal the department’s determination. The notice comes as a central Ohio judge is weighing a legal dispute over how head counts for the school and other online charter schools in Ohio are determined.

The issue has been problematic because students at online schools may do much of their learning, such as homework, reading and projects, while not logged onto a computer. After attendance questions arose under an earlier system of self-reporting, the state tightened its attendance tracking method.

The Electronic Classroom tried to block regulators’ access to student log-in and log-out information, charging the education department’s new rules violated its agreement with the state and couldn’t be imposed retroactively.

The court ordered the Electronic Classroom to turn over a sample of student log sheets, which the department used to come up with its total enrollment.

A school spokesman criticized the process as “a sham.”

“We strongly disagree with ODE’s letter, which is why we are already in court,” said spokesman Neil Clark. “We knew this process was a sham and ODE’s actions prove it. They have and continue to railroad all e-schools in the state. It is impossible for any e-school to meet the retroactive demands of ODE, which is why no e-school in the state has been able to do so. ODE made arbitrary requirements and then applied them retroactively.”

In his letter, Aaron Rausch, director of the department’s budget and school funding office, said the e-school turned over 706 records, representing what it self-reported as equivalent to 414 full-time students. The department found the records amounted to only 171 students, or 58.8 percent less than what was reported. It then extrapolated that percentage to the school’s entire reported enrollment of 15,321, determining the school is educating only 6,312 students.

Ohio bases a school’s funding total on how many students it educates.