check March 08 VB section D

D. EMPLOYMENT VISA AVAILABILITY
Here is the quote:
"The cut-off date movement for March in several Employment categories has been greater than those experienced in recent months. Advancement of the cut-off dates at this time should prevent a situation later in the fiscal year where there are large amounts of numbers available but not enough time to use them. If the expected increase in CIS number use materializes, future cut-off date movements could slow or stop. "

No indication that the rapid advance of Chinese EB2 cut-off date occurs as a result of using the unused visa number from other countries. It is differnet from the current situation: India is allocated some quota from the visa pool while Chinese is not .