GOP senators on the Budget Committee want the Congressional Budget Office to do a real-world test of its updated health insurance simulation model -- which estimates coverage and premiums for the under-65 population -- by redoing the initial Affordable Care Act coverage and spending estimates to see if they would match more closely to what has transpired. The lawmakers also ask to see more details about the model (dubbed HISM2) before CBO uses it to develop 2019 baseline projections and...