You poor thing ... lucky that there is the net. I was helping a friend with this problem and it took me a few days to figure it out. Hehehehee ... Its simple. If the difference is very little, a click or two then there is no real issue but if its more than just a couple of clicks then you will have issues. Your problem may be that the motors will not be giving the same amount of thrust. You can check this with 2 watt meters. This is usually caused by cheap ESCs. We had that problem with the cheap ones and when we changed to branded ones it was resolved.