The auto machines are quite intelligent, and use sensors, together with a program to adjust pressure based on detection of flow limitations, snores and breathing volume changes. They work best when the minimum pressure is set closer to the required therapeutic pressure. Maximum pressure is not so critical as long as it is high enough to treat the obstructive apneas in any body position or sleep stage. The prescription is very good, and is a reasonable range that she will probably narrow as time goes on. It provides for your needed supplies for life.
Good luck in finding a good deal and please don't hesitate to have your wife join here. Success is improved with support and information like what she will received here.
You are getting sound advice in your replies so far. From experience I recommend that you stick with a known brand CPAP. I accepted a machine that is not in the mainstream (out of lack of knowledge) and have real doubts about it. If you need to make a decision and need help this forum will produce quick responses and a day of delay, if it comes to that, would be well spent.
Also, if you haven't already, make sure you get a hard copy or an electronic copy of the complete sleep study including recommendations. Good luck!