"Shared responsibility" is the name given to the new tax penalty that Americans who were uninsured in 2014 must pay this tax season to comply with the Affordable Care Act. In numerous reports, it's been suggested that the most any one family would pay would be $95, times the number of uninsured household members.

Here's the bad news: It could be more than that.

A friend of mine, Christine and I discovered this the other night when we prepared her taxes together using online software. Christine and her husband Joe didn't have health insurance last year, though their children were covered through New York's Child Health Plus program. They felt the premiums through his employer and through the state's health-insurance marketplace were unaffordable, so they decided to go without. They didn't fit any of the numerous exemption statuses to avoid the tax penalty. So they figured they'd just pay the $190 ($95 x 2) and move on.

But when we ran the numbers through H&R Block software from IRS Free File, as well as TaxACT, the penalty came to $273. Neither software package explained how that figure was derived.