from scratch a theoretical guess usually suffices and then you just fine tune it from there. But there are a lot of small changes you make to get things right and fenaggling through a bunch of different screens with digital buttons is difficult simply because there are a lot of parameters to click through. I haven't seen the PFC's controller, I've only the experience of other management systems so I'm just trying to get an idea of how easy it is to use. Obviously its not because I want to buy one, but I'm just asking the question. The user friendliness aspect and ease of use has been my primary goal of the ZEM interface because of my experience with hand controllers in the past. It is a big consideration when you are talking about making changes to engine parameters.