L2 does not show all orders. There are typically orders that are not large enough share-wise to meet the threshold (usually 10,000 sh) which do not show on L2, and of course All or None (AON) orders, which I use a lot with stocks like STWS, never show up on L2. A typical example is when one places a limit order to buy shares at the Ask for a larger number of shares than is currently offered at the Ask, and the order will fill for at least the number of shares posted and offered at the Ask, but not a complete fill, and then the remaining portion of the order may or may not show up as the new higher bid, depending on the remaining size, and what the threshold is in the particular shares. That has happened to me here with STWS.
