I agree, I have this one too and it works fine for my needs.This one is good enough to get the trigger set where you want it. It does not need to be a high dollar calibrated instrument.
I have the Lyman digital and the Wheeler; both work as advertised. As you did, I followed the instructions, took multiple readings, and averaged them out.I've been using the Lyman digital which seems to work pretty well,but no matter how hard I try to keep the same angle on the trigger and the same method and rate of pull on the scale I still get variants of a few ounces between pulls.My target weight for the TT Diamond was 8 ozs. and pulls ranged from 6-10 ozs. so I just averaged out 10 pulls and came up with 8 ozs.I have seen guys loop a string around the trigger with a hook on the end(rifle standing up on butt)and then hang lead fishing weights on the hook until the trigger breaks,seems the most reliable but I'm ok with the Lyman digital.
That’s the unit I use. It gets me to a good idea of where I’m at. In the end it’s about how the trigger works for you. If you experience AD’s during dry fire there are two ways to manage it…dry fire until muscle memory makes it natural and safe, or increase the weight until the same thing is achieved.This one is good enough to get the trigger set where you want it. It does not need to be a high dollar calibrated instrument.