For my F Visa in 2009 I had multiple entries and exits from China and was in China for less than the maximum 183 days. That Visa expired in Jan 2010.
For my new F Visa which is one year multi-entry issued on Jan 12, 2010 is the 183 day maximum days in China counted A.) from January 1, 2010 to December 31, 2010 OR B.) from February 1, 2009 to January 31, 2010 AND then from March 1, 2009 to February 28, 2010 and so on for each month during 2010 so that it is counting the number of days in China for the current month plus the prior 11 months?