A coalition of patient advocates is urging HHS to address high out-of-pocket costs by demanding that insurers selling marketplace coverage strictly adhere to the Affordable Care Act’s rate-setting requirements. Insurers have strayed from the mandate in recent years by underpricing silver-tier plans and overpricing the more-generous gold-level products, the advocates say, highlighting an issue that experts have been raising for years and that some states are already addressing at the local level. But health experts also say that HHS must...