There’s a useful tool called “Crosshair & Tooltip” (or “Pointer & Tooltip”) showing the percent of price change between two points on the chart.
This is intended to be extremely useful by showing our interest in case that change we drew realizes. Here you can see, the data is called “Difference”.
The problem is that, literally it lies. That percent shown is not true because it uses two Buy Prices only, as if we could sell shares on Buy Prices. But we sell on Sell Prices.
So we should see the difference between a Buy Price and a Predicted/Estimated/Most-Likely Sell Price. Of course, correspondent Sell Prices could be retrieved from past data.