Yes, I am certain, and this statement is not correct:
So an offer to sell 5 shares shows up as 100.
Actually, any size less than the minimum - in this price range it is 100 shares - will not be displayed on Level II at all. 101 shares available and 199 shares available will both be rounded down and displayed as 100. 99 will not show up at all, but if the same market maker has two or more orders that meet the minimum size when added together, the total of the orders will be posted (and rounded down to the nearest increment of 100).
You see 100 because that is the minimum to display and, contrary to popular belief, market makers do not always have to display the actual size they have available - so 100 could mean 100, or it could mean a larger size.
