Can an employer (of an automobile dealership) take/deduct wages and/or commissions and consider it a “disciplinary action”?

For example, if customer survey results do not meet or exceed a standard, which would be different for each month based on the district’s overall score, can an employer refuse to pay earned commissions or deduct an amount from earned wages/commissions?
Also, this decision to deduct or withhold an amount would not be made until the end of the month, after all hours have been worked and all commission based on gross earned has been calculated for the month.
Any and all advice or directions on where to find information concerning the previous would be greatly appreciated. I have found the following:
“Under Tennessee laws deductions can only be taken out of pay if the employee has authorized it either written or verbally. And if the employer tells the employee prior to hiring that deductions will be made for uniforms, etc. as a condition of employment.”
But I don’t believe that concerns deductions considered as disciplinary action results, at least the wording that is used here. (But I could be seeing what I want to see.)

"Deductions" used in this context are deductions from NET pay, not reductions in GROSS pay. As long as you are paid at least minimum wage, and the commission agreement specifies that commissions may be adjusted based on such subjective criteria as customer service surveys, this would not appear to be a violation of any state or federal wage and hour law.