What is the maximum dose of mixed amphetamine salts?

Question from a Member: I inherited a patient on [mixed amphetamine salts] extended-release [brand name Adderall XR®] formulation at 60 mg per day. This dosage seems awfully high compared to the standard for daily dosing of the extended-release (versus for immediate-release). Am I correct to be concerned from the medico-legal perspective? Our Member’s question has…