When you find a timing light you trust do not lone it out. I was and idiot and loaned mine to a college educated mechanical engineer. Two times I told him to lay the wires out of the way. Yep. Five minutes later he came back with my timing light wires almost melted through. He bought me a used piece of she- ite from Facebook. Yaaa it’s worked real well.
THIS^^^^^ All timing lights have a slew rate. That affects what they read. Pick a light, tune with it and stick with it. What it says is far less important that tuning with the same light.
