Those torque sticks are no where near as accurate as a good torque wrench. This assumes that the torque wrench is in calibration. which should be done every 2-4 years. There is no way to verify that a torque stick is accurate, and no way to calibrate it out, either. A calibrated torque wrench is normally accurate to within 4%; a digital torque wrench to within 2%. What is the accuracy specification of a torque stick? (Not being a smart ass, I really don't know, but would like to).
On my 1993 Lincoln Mark VIII, the torque spec was 80-100 ft. lbs. Mechanic asked me the torque spec, and I told him. He used a yellow coloured torque stick, out of a selection of 6-8 torque sticks of various colours. Since I don't trust anybody who uses an impact to tighten lug nuts, with or without a torque stick, as soon as I got the car home, I got each wheel up with the car's jack, and loosened the lug nuts. Took a 24" 1/2" breaker bar, with me practically standing on the bar (I weighed 210lbs. at the time) to get them loose. No way were those lug nuts torqued to less than 160 lbs. or so. I retorqued them to 90lbs. using a recently calibrated Snap-On torque wrench. The Mark VIII had undersized disk brakes in the front, so over torquing the lug nuts often resulted in warped brake rotors due to the heat generated, so I was very careful to make sure that the lug nuts were properly torqued (you can figure our how I came to that conclusion pretty easily).
And, by the way, you shouldn't be using regular sockets with an impact gun (pneumatic or electric). Normal sockets are a thin wall design, designed to get into tight spots. They are not designed to be used with impact guns. In places with clearance, use a proper impact socket, usually matte black in colour, and much heavier in construction. Regular sockets can actually break or even blow apart when used with an impact gun.