Linear Regression Canal ?

 
I wrote indicator for linear regression line.
I used many different data for calculation - OHLC med. typical etc.
but unfortunately line still is not exactly accurate with Linear Regression Canal drawn by MT4

What is the data used to draw Linear Regression Canal ??

Regards
 
I wrote indicator for linear regression line.
I used many different data for calculation - OHLC med. typical etc.
but unfortunately line still is not exactly accurate with Linear Regression Canal drawn by MT4

What is the data used to draw Linear Regression Canal ??

Regards

I believe and I have tried it, it is simply trend line object drawn between two points p1/t1 and p2/t2 where t1 - t2 is the period and p1 - p2 should be linear value calculated based on High, Low, Open or Close depends on your application.
Reason: