Most APAP machines can automatically adjust between 4 and 20 cmH2O pressure. However, they can be set to adjust between a narrower range of pressure. If the full pressure range doesn't work right for the patient, you can set it to a narrower range. For instance, instead of a single pressure of 10, you might set the machine at 8-12. If that pressure causes problems, you might use 9-11, and still get some of the benefits of auto pressure adjustment. If you set it to something like 9.5 to 10, you're basically using manual CPAP.
As far as I know, all APAP machines can be set to have the minimum and maximum pressure settings be the same, which is the same as manual CPAP.
You can go full APAP, but you can also "turn down" the range of the auto until you find the range that works. That's why an APAP machine vs. a manual CPAP machine is always the right answer.
The critical thing is to get a fully data capable machine and monitor the data that it collects. It's like having a mini sleep test every night.