It maps out the real world closing price vs the Heikin Ashi closing price. I think I'll make the indicator a mainstay of my trading charts, as it's useful to see. It also makes manual backtesting more viable.
Some interesting observations:
Long-term average difference between real world closing and HA closing ranges from 1 - 4 pips.
There are intermittent spikes of up to 10 - 12 pips. These happen fairly infrequently (depending on the time frame being viewed).
On average, HA prices are closer than I thought to real world prices. I would have expected an average greater than 1 - 4 pips.
Spikes in difference often signify important points. Primarily they seem to signify new or continued trend activity in the relevant direction, but sometimes they can indicate tops or bottoms. Could be interesting to try and build a strategy around it.
I'm not sure if I'll publish the Real Price indicator (it's literally just a few lines of code), but let me know if you want a copy of it.