(eff. beginning with 2012 Forms W-2 to be given employees by end of January 2013)(IRS modifies prior interim guidance concerning health care act's reporting requirement for employer-sponsored health coverage; IRS notes that effective Jan. 1, 2011, aggregate cost of applicable employer-sponsored health insurance coverage must be reported on Form W-2; reporting optional for 2011 and IRS later provided relief for small employers (where less than 250 Forms W-2 filed for preceding calendar year) by making such reporting optional through at least 2012; IRS notes that reporting requirement does not apply to coverage under FSA if contributions occur only through employee salary reduction elections).