What we are looking at here is current commercials net position approaching its 36-month (156-week) high or low. It is a parameter and can be changed manually and backtested.
Essentially, we are looking for net position extreme points within some considerable period of time.
Still, using this indicator we have to keep in mind that commercials are hedgers, they are selling product they own. It means, occasionally we can see Com. Net Position making successive lower lows with price making higher highs at the same time. Good example is year-to-date silver rally. My point is that this indicator is not a precise one, it only can give us a hint on what business anticipates in a long-term. So we have to be patient and look into price action on a smaller timeframes to determine entry points basically.
I suggest the following reading for further study of Commitment of Traders report -
Trade Stocks and Commodities with the Insiders: Secrets of the COT Report by Larry Williams https://www.amazon.com/Trade-Stocks-Commodities-Insiders-Secrets/dp/0471741256