The appellant challenges an administrative order by which the Department of Revenue (the department) sustained a tax assessment. In this order the department rejected several critical findings from a recommended order in which a hearing officer determined that the assessment should be rescinded because the appellant had already paid the necessary tax. We conclude that the hearing officer’s findings were based on competent substantial evidence, and that the department exceeded its authority under section 120.57(l)(b)10, Florida Statutes, in rejecting these findings. The challenged order is therefore set aside.