Resmed s9 adapt AV and s9vpap stax

I need help I have been having trouble with sleep apnea for the past 2 years. Over the last 9 months they are now saying I am also having centrals quite bad I just went to hospital so the doctor could change the settings every night to fine the right one. He did find what I needed and I hired a machine for a month till I could get my own again this is the third one I have purchased have been trailing a Phillips respronics for the past week and now having major problems it's the same script. I am thinking now of going back to Resmed but it must be spontaneously timed I can't figure which ones which. I'm live In Australia and the S9 vpap sta with climate controlled humidifier is $6000 And the s9 vpap adapt sv and climate control is $3500. Problem can I get away with purchasing the cheaper one and well it do the trick my pressure has to be 25. Please help thanks

Just a helpful bump, in case the unregistered guest is still looking for an answer.

The VPAP ST-A does iVAPS mode in addition to S, ST, T, and PAC modes. The VPAP Adapt is an ASV machine.

They do different things. The iVAPS mode is for hypoventilation, and the ASV mode is for central apnea. The ST-A also does a higher pressure than the Adapt.

Do you actually need the S9 ST-A or would the S9 ST do? The VPAP ST does self timed mode, but not iVAPS.

Why are you talking ST mode? It seems that ASV mode is more common these days for treating central apnea.

BTW, I think there is no S9 VPAP Adapt SV. Adapt SV is used on the S8 series. The equivalent S9 is just called VPAP Adapt.