My question involves child support in the State of: Nebraska

I recieve child support regularly from my ex thru the nebraska child support department. But lately, my checks have been smaller than what the court order says. Does this mean that my ex is not making his regular payments and are falling behind or is it because the nebraska child support department is taking out taxes for their services? I did recieve a notification in the mail that stated since I am recieving over $1000 in child support they will take only $25 from my checks for the whole year...that was if I was reading it right. Not that Im complaining about the deduction and such, I just would really like to know what is going on.