Companies putting together 2011 health benefits–and many have already begun the process–are in the uncomfortable position of having to make big-dollar decisions before some of the blurry language in the healthcare reform bill is clarified. The first complicated requirements set by the Patient Protection and Affordable Care Act go into effect for plan years starting after Sept. 23. "People are not appreciating how much of this law we won't know for a long time," says Susan Relland of the law firm Miller & Chevalier, who's a board member at the American Benefits Council.

Probably the most significant provision says employees' children under 26 who are not enrolled in another group plan must be allowed to enroll in company plans in the next plan year, which for most companies probably starts Jan. 1, 2011. Beginning in 2014, plans must cover children up to age 26 whether or not they have access to another plan. Companies are considering whether to face the administrative hassle of determining whether adult children have access to other plans or just let all employees' children up to age 26 participate starting with the next plan year, explains Relland.

"Inclusion of adult children up to age 26 has been the No. 1 question raised by our clients," says Randall Abbott, senior consultant at Towers Watson. However, he doubts companies will decide to cover all adult children. One scenario, Abbott says, is that a company could set up a separate rate category for adult children and levy a different charge.