Unprofessional conduct occurs when 1) Charging a fee for services not rendered or dividing a professional fee for patient referrals among health care providers or health care institutions or between these providers and institutions or a contractual arrangement that has the same effect. 2) Obtaining a fee by fraud, deceit or misrepresentation. 3) Charging or collecting a clearly excessive fee. In determining whether a fee is clearly excessive, the board shall consider the fee or range of fees customarily charged in this state for similar services in light of modifying factors such as the time required, the complexity of the service and the skill requisite to perform the service properly. This subdivision does not apply if there is a clear written contract for a fixed fee between the physician and the patient that has been entered into before the provision of the service.