"[R]equiring employers to master the laws of 50 states and to submit different data sets, at different times, in different formats, for different populations would impose substantial burdens on self-insured plans. These significant costs would ultimately be borne in whole or in part by plan participants ... [We] ask that the Committee report and the subsequent DOL guidance to the states, state clearly and unequivocally that states cannot require self-insured plans to report to state APCDs."