There is a stock that is showing 4800 shares on the bid and 9900 shares on the Ask at Island book viewer. But level II is showing 91 CINN on the Bid and 3 CINN on the Ask. Furthermore the figures of CINN on level II are changing while nothing is changing on Island.
CINN is the high bid/low offer from ISLD that you see on your L2 screen. the ISLD book holds the depth of the ISLD market behind that high bid/low offer. i don't have an integrated L2 book, so that's all i know. hope it helps dude...