I know what the bid/ask/last prices represent, but in Think or Swim, these prices are completely different from the prices show on my candles. What gives? For example, right now, at 11:00 AM, the pricing is as follows: Last...784.75 Bid.....784.00 Ask....784.50 But then my candle is showing 786.25. What gives? What price does the candle represent?