NEW YORK (CNNMoney) —The Affordable Care Act's price tag continues to fall.The president's landmark health reform law will cost $506 billion for the coming five fiscal years, according to updated projections from the Congressional Budget Office, released Monday. That's 29% less than the agency's projection back in March 2010. Among the reasons for the decline:-- The Supreme Court's 2012 ruling that allowed states to decide whether to expand Medicaid. -- The continued slow growth of health care spending. -- Enrollment in Affordable Care Act insurance exchanges has ramped up more slowly than anticipated.In its latest projection, CBO also revised its...