"[E]xposing PBMs' opaque business practices and imposing regulatory constraints will remain a top priority for regulators.... Even before a statutory or regulatory elimination of spread pricing, health plans should begin to consider now how this change could impact current and future PBM contracts ... [It] may be worthwhile to consider now the various channels for PBM profit available under your PBM contract, and whether you can begin to limit/narrow (or consider limiting/narrowing) those avenues for PBM remuneration that exceed the scope of 'bona fide service fees.' "