Need HELP with new machine

I used a Respironics Pro2 for approx. 10 years I loved that machine, never a problem breathing, it was my safe haven. It was getting old and the on/off button was starting to stick so I figured I better get a back up machine. To make a long story short I ended up buying a Resmed Aircurve 10 Vauto.....it came to me already programmed...I was expecting a new safe haven, that's not what I got. The first night I kept waking up with low oxygen (low 80s) and had difficulty breathing, just couldn't seem to get enough air in. Had to breathe out through my mouth and oxygen stats would finally rise to 90 or 92 but sleeping was impossible, too hard to get air.
Finally decided to go back to my old machine, only to find that it no longer starts, now I'm stuck with the new one. I'm hoping there's some setting that is available to help. I've tried so many things and pretty sure it has to do with the humidifier, breathing gets a little easier when humidifier is turned off but still not comfortable enough to sleep. Right now the only way I can sleep is to use a canula for my oxygen and wear it under the mask instead of running the oxygen through the machine, oxygen stats stay between 94 and 98. and breathing is better, almost perfect. I did notice a setting on my old machine of Flex 3 and don't see anything about flex on the new one, probably named something else? Any ideas? Please

old Pro 2
Ramp start 7.0
Ipap 16
Epap 11
Flex 3


Aircurve

S mode

Ipap 16
Epap 11
Easy Breathe On
Ti Max 2,0
Ti min .3
Trigger medium
Cycle medium
Ramp time off

What pressure setting were you using on the old Pro2?
What mode of operation along with pressure settings are you using on the new AirCurve?
Are you using the ramp setting?

ResMed machines don't have "Flex" exhale relief but they have something else that works toward the same goal.
EPR in cpap mode on your new machine...but not in the bilevel modes because bilevel itself works like EPR works.

old Pro 2
Ramp start 7.0
Ipap 16
Epap 11
Flex 3


Aircurve

S mode

Ipap 16
Epap 11
Easy Breathe On
Ti Max 2,0
Ti min .3
Trigger medium
Cycle medium
Ramp time off