Phil
I am not sure I have understood what you are asking, never the less here is an efs that will paint in red the bars that have a High-Low range less than a user defined point or percentage amount.
The percent value is based on the mid point of the bar (ie as if you were using a 1 period Envelope based on HL/2).
Load the efs in the chart then in Edit Studies select whether to use Points or Percent and then input the Value for either of the above.
In the sample image below the efs was set to Points with a Value of 15
Alex
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