No insurer, its officers, or managers shall require licensed property and casualty agents to sell a specified number of life or health insurance policies or a specified dollar amount of life and health insurance as a condition of selling property-casualty insurance. No insurer, its officers, or managers may reduce or restrict an agent’s underwriting authority on property-casualty insurance policies based upon the sale of life or health insurance. The provisions of this section do not apply to agents who are directly employed by the insurer or who write 80 percent or more of their gross annual insurance business for one company or any or all of its subsidiaries.