Child support order for adminstrative fees only

This is a case in Wood County, OH:

I was named the residential parent in August 2009 after negotiating a shared parenting plan with my ex-wife. In December, 2009, an agreement was made to waive the child support arrears to $600 at $50 a month plus an administrative fee. In February, 2010 my federal and Ohio tax refunds were intercepted. The CSEA said they had the right to take a lump sum and I didn't argue considering all the back child support was now paid. I asked for the excess amount to be returned to me and when my child support order would be terminated. The representative from the CSEA, who was a supervisor, stated when I received the check for the overage, it would be a good indication my order would be terminated. For 10 months, I haven't see any correspondence from the CSEA until this month.

Earlier this week, I was mailed an income withholding notice for child support, which was sent to my new employer. It stated I owed child support, which was more than 12 weeks in arrears. When I called the caseworker, she stated all I owed now was administrative fees. Also, I checked my credit report and it only shows on one reporting agency. Not only that, but now my employer thinks I'm some kind of deadbeat just from how the support order was worded. My question is whether my income can be garnished for just administrative fees alone?