I've been using this tester for about 5 years, it's been on 100's of trucks, I also use a Snap On Modis that has cylinder/power balance. The G2 will condemn a injector with >350ms (milli sec) of stiction, you will never see that in a cylinder balance test, NEVER. So, on a cold start you have stiction, that stiction effects the way it starts, as so as the engine starts the stiction will begin to diminish, sometimes it gone in <30 seconds, temperature also effects stiction, but the stiction still effects start up. You can't do a cylinder balance that quick or on a cold start up. A truck that has 275-350ms will start and run "alright" in 40*F, but a 300k mile 6.0 in -14F* with 245-255ms of stiction will start better than any other diesel. Just 25ms of stiction make a big difference. I did make a video of the -14 cold start, I'm not sure how to post it tho.
I know the results you get from a cylinder balance test, I've done plenty, then I also know the results of stiction and the effects it has on a 6.0.
Over the years I've read plenty of posts about cold start, ruff running and smoking issues on these 6.0's and I was always thinking if they could only see how much stiction they had in their injectors, but I never said anything because I knew nobody had a way to check it and bringing it up would just cause a fight, so I just mentioned it in this post because the OP posts on and tries to help other people and obviously know this engine well. I won't bring this tester up again.