I have created a few designs for a couple of months and always when I let them produce with SMT at JLCPCB, with the option that I choose the location of the tooling holes, I am getting mixed results. Most of the time they contact me before manufacturing that my tooling holes are not correct. [https://support.jlcpcb.com/article/92-how-to-add-tooling-holes-for-smt-assembly-order](https://support.jlcpcb.com/article/92-how-to-add-tooling-holes-for-smt-assembly-order) states that the tooling holes must be 1.152mm or 51.4mil. I used to work in mil in my designs. However when I use 51.4 mil and then switch to mm the holes changed to 1.153mm (and not 1.152mm). If I use a 1.152mm hole and switch to mil I get 51.34mil (and not 51.4mil). However, when I post the designs (51.34mil or 51.4mil) to JLCPCB they always need to correct them. So my best guess is that sending in a design based on mil (not mm) will never provide the correct dimensions because their software converts mil to mm in another way. Should I post in mm instead of mil? Anyone has a clue? I will ask JLCPCB also the same question.