Are Virginia Public School employees considered State employees to qualify for schedule adjustment code 39?

My wife is a Virginia Public School employee (special needs school bus aid). She made less than $15,000 for tax year 2020, so we used schedule adjustment code 39 for Federal and State employees. Two years later the Virginia Department of Taxation adjusted this return to remove the State employee tax reduction. Per discussion with Virginia Department of Taxation customer service, they consider my wife a local government employee and I have been asked to provide supporting information that she is a Virginia state employee.  I have these comments to submit, but I cannot find a reference that specifically says Virginia Public School employees are State employees. Any help you can provide will be greatly appreciated. 

- She is actively participating in the Virginia employee retirement system. (VRS).

- The bus she works on has Virginia State government license plates.

- Her school is licensed and accredited by the Virginia Department of Education (VDOE).

- Funding for Virginia Public Schools comes from state governments.

Code 39

Federal and State Employees - Any individual who qualifies as a federal or state employee earning $15,000 or less in annual salary from all employment can subtract up to $15,000 of the salary from that state or federal job. If both spouses on a joint return qualify, each spouse may claim the subtraction. The subtraction cannot exceed the actual salary received. If you claim this subtraction, you cannot claim a Credit for Low-Income Individuals or Virginia Earned Income Credit.