Wisconsin's controversial 2011 collective bargaining law may add $87.5 million to state retirement system costs next year due to a little-noticed change that will boost employee benefits.

The unanticipated costs aren't a back-breaking amount for the massive retirement fund, but they illustrate why laws that alter the complex retirement system should be examined carefully before enactment, said Robert Conlin, secretary of the Department of Employee Trust Funds.

Conlin's predecessor, David Stella, stepped down in January saying that elected officials disregarded his plea for a thorough examination of how changes in the law would affect the $82 billion pension fund.