Yes, pretty sure you could miss out due to the algorithm, where $20 is the result of a calculation of all the orders in the active range. So you probably noticed some bids that were over $20 and some asks that were under $20.
It's a bit of a game, get to the top of the queue, maybe with an asking price of $16, while not lowering the CSPA price from where it currently sits. And in reverse for buys.
So you were quite probably pipped at the post by some lower sell prices, even though they actually got $20 per share.
