"Maximizing participation may be the goal in most cases, but plan consultants in tune with their clients' businesses should recognize instances when immediate eligibility and/or automatic enrollment are contraindicated.... industries with very high turnover, such as the restaurant, landscaping, or car wash industries are better served by a one-year waiting period before automatic enrollment takes place. ... Similarly, there can be circumstances in which allowing employees who work less than 1,000 hours per year to participate causes the previously small plan to exceed 120 participants, requiring a financial statement audit to be attached to the Form 5500."