In my case, when i fill large quantity order usually on expiry day coz of low price of call/put, I disclose only 10% of my order. This feature I believe avail in every trading platform. So, lets say 100lots of bnf means 3000 quantity, and visible only 300 at price of 11-15 (assume), It is not a difficult to full fill this order. You can try on this thursday.
Thanks
rip07