NASHVILLE, Tenn. -- Employers are just beginning to learn the financial ironies of the federal health law. Small nonprofits that pay no taxes can get tax credits. Some businesses that currently provide generous insurance may stop. And organizations could fork over more money covering part-time workers than full-time workers. While the Affordable Care Act will provide access to insurance for millions more Americans, it is not a law of equality for employers. The impact differs according to how an employer's workforce is structured and the generosity of its health benefits.