Chris,
I hope you understand the spirit in which I am giving this advice. I am not trying to berate you or make light of this. I honestly find this alarming. We are in compliance with the wiring standards. I am worried you may damage your welder from continuing to operate it without wiring it properly...

First, Have you downloaded and read the manual from the website? It concerns me because it is addressed in there, as well as other important issues that you need to know about, some of which will save your life.

Second, We have dozens of threads about this. We have discussed it with you here, and it is in the manual. Your electrician sounds like he is not qualified. If it were me, I'd fire him and get a new one that understands how to wire a welder, rather than a stove or dryer. STANDARD wire colors for 220V welders in the US are : White=HOT, Black =HOT, Green Ground. No neutral at all. A neutral is a return path for a 110V circuit such as a clock or something on a stove. (though there are other uses) There is no need for this on a welder. And NO don't wire the green to the neutral...It is a ground....It should go to the ground. Also the back of the panel should be grounded to a dedicated ground attached to a ground rod outside to control HF emissions. Red is only to be used on a dual phase/voltage machine for the 3rd phase. What you have described is EXACTLY what will happen when you have it miswired. Yes, when you press the switch, the machine changes the display to read ACTUAL output.

In other words, you should (for simplicity's sake) wire green to green, black to black, white to red, since this seems to be your input colors.

Third, you should NOT be using the 14-50. The standard welder plug in the USA and Canada is the 50 amp/3 pronged NEMA 6-50...which most brands HAVE the wire colors printed on there just as we have the unit wired.

IF after you connect this properly, you have no improved results, I can only say you have damaged the welder from miswiring it.