A quote is not a fill

Record the information visible when you make a practice decision separately from the price at which an order actually executes. The last traded price, bid, ask and eventual fill describe different things. A chart label is not evidence that your entire quantity could have traded there at the relevant moment.

In a simplified quote, the bid is the displayed buying side and the ask is the displayed selling side. Their difference is the quoted spread. A market buy will generally execute near the ask and a market sale near the bid, but prices and available size can change. A midpoint is a calculated reference, not an execution promise.

For an honest exercise, keep a timestamp, quote source, quantity and example type beside the price. If you are using a historical chart without quotes or order data, label the fill as assumed. Do not later describe a profitable result from that assumption as something a member or Brock actually earned. A transparent missing field is more informative than a precise-looking number with no source.