For most people running an APAP wide open is less comfortable than running it in a tighter range. If the min pressure is too low, too many events will have to happen before the APAP's auto algorithm kicks in and raises the pressure to something close to what's really needed to keep your OSA under control. If the max pressure is too high, there may not be any problem, but if you are prone to aerophagia or centrals, a max pressure that is too high can be problematic.
I have a question: What's wrong with setting the new machine with the old one's settings of min pressure = 6 and max pressure = 18 for the time being and seeing what the data says is going on after a week or so?
Did they set they pressures for you when you got your new machine? You can either have a min and max or the min and max can be the same which means you basically have it in straight CPAP mode which really defeats the purposes of having the Autoset. If those pressures were working for you, I would set them at that again. If you go to the top of the page you can download the clinical manual. Your pressures will show on in the software anyway.