Calipers are difficult to use, even more difficult to use on yourself. Better off sticking to how clothes are fitting, the tape measure, and photos.
Do you have a specific goal you're shooting for?
I presume you've been progressing in the gym as well? Consistent strength gains are another way of making sure you're moving in the right direction.
Like Dt said, don't base your decisions on what an article or someone "says" you should be doing. Train and eat a certain way, see if you get closer to or further from your goal, and make adjustments if necessary. If you've been seeing steady results with GVT, stick with it a while longer.