Question: How to limit an employee's ability to view the costs of billable items?
Answer: An employee right is available to prevent employees from seeing the cost of a billable item when adding via quick invoicing, creating an estimate, or adding to a treatment for a patient. They will also not be able to view the cost on items when expanding their details from the medical record.
By default this new right will be selected for newly created employees and can be enabled for existing employees by anyone with the ability to manage employee rights, it can be found under the Medical Records section
For more information, you can view the article on Employee Rights