What is a "supplemental" motor vehicle tax bill?

If you newly registered a motor vehicle after October 1 (first time registration), you will receive a prorated tax bill in December of the next year, payable by February 1, of the year after that (example you registered a motor vehicle after October 1 of 2010 you will receive a bill in December 2011 payable by February 1, 2012). This "supplemental" bill will reflect the time from the month the vehicle was first registered, through September 30, only.