This script automatically calculates and updates ICT's daily IPDA look back time intervals and their respective discount / equilibrium / premium, so you don't have to :)
IPDA stands for Interbank Price Delivery Algorithm. Said algorithm appears to be referencing the past 20, 40, and 60 days intervals as points of reference to define ranges and related PD arrays.
Intraday traders can find most value in the 20 Day Look Back box, by observing imbalances and points of interest.
Longer term traders can reference the 40 and 60 Day Look Back boxes for a clear indication of current market conditions.