"While the DOL has not yet issued meaningful guidance as to what specific actions are required by responsible plan fiduciaries with respect to these obligations (especially with respect to the assessment of whether fees are reasonable), ... the attached Checklist [is] a practical guide for responsible plan fiduciaries to address their initial obligation when they receive the relevant disclosures from service providers -- to review the disclosures made by the service provider and confirm that there are no obvious errors or omissions so as to be able to form a reasonable belief that the required disclosures have been made."