Take Carnival (LSE) for example, the price it closed at yesterday in the box was 919 for buy. However, the graph showed the price ending at 936. Having faith in the box, I placed a buy order at 919, but the position never opened. The stock opened at 930, leaving my position closed. I am wondering whether to trust the box or the graph since other orders have been true to the price in the box. Is there an indicator that I can look out for?