You can look up the datasheets yourself. I have a PDF of one somewhere I will try to find a post.

Just because yours read true doesn't mean they are accurate. When the manufacturer lists an error of +/- 4 F they do so because they know the limitations of the components used. The point of a toll wrench is that it is a range. Sure it can read spot on, but another day/another temp gun of the same model could be + 4 F. Some of my Acu-Rites read true, others not so much. The facts of the matter is that you are getting something rated for the same tollerence. A temp gun $50+ is going to be better, but is it 5x better?