If an employer implements a premium discount program for non-smokers that meets all of the requirements of a "bona fide wellness program" as set forth in the most recent HIPAA regulations, and an employee who is a smoker decides to participate in the smoking cessation program mid-year, does the employer have to rebate the additional premiums that such employee paid prior to participating in the program? (or does the reward--the lower premium--only apply to the time after participation?)