"[T]here are two types that the administrator can instruct the auditor to perform ... The difference between these two audits with regard to audit procedures is that in an ERISA Plan Audit, the 401(k) Plan's investment information is subject to audit procedures, while in an ERISA Section 103(a)(3)(C) Audit, the auditor will not perform audit procedures on the investment information that is prepared and certified to be complete and accurate by a qualified institution."