I stand by the video. Its accurate. A positive displacement pump (diaphragm) will have small pulses, its design of the pump. The gauge is accurate it is designed to detect fluid pressure. Anyone that wants to test it may do so. The pulsing is less than 5 PSI, its not severe as eluded to. As pointed out pulsing is natural to any postive displacement pump and the gauge is simply reading that.
The glycerin filled gauge and a snubber basically do the same thing they soften the pulses.
In terms of pressure output this test is accurate.
Again, this is our pump.