I have court a week Tuesday!
I know they cut close to the scalp and an inch and a half will tell you a 3 month time line!
It takes 7-10 for the drug to grow out enough to cut it!
So I have been doing it on and off for a couple weeks if they only test and inch and a half what will the results of my test be??
And do the detox hair shampoos make a difference?

Detox shampoos are a waste of money and don't work. If you have "been doing it" off and on for a couple of weeks they'll certainly know once they take your hair and test it. They cut very close to the scalp BTW and you're going to get caught. Be sure to have your affairs in order when you go to Court.

Yes and they can find longer non cut hairs in other parts of the body if they do not have long enough ones on your head