Hi there dear friend Apprentice, I searched in the forum and couldn't find this one.
Request for MT4 ok?
Here is the formula:
https://onlinelibrary.wiley.com/doi/pdf ... 31877.app3
You can add an option in the indicator settings panel to choose the calculation method using tick volume OR no volume.
Also, I think it will be easier and faster to use the indicator if instead of the user having to type the date/time of where to start the calculation, it would be better if you could drag a vertical line wherever you want it to start from. And please add an option to choose the color of the vertical line too, so you can blend it with the background (less clutter)
Thanks!