Obstructive or Central

Just wandering if my brain is holding up in differentiating Obstructive from Central.

Obstructive shows a flat line in the Flow Rate.
Central, air way open, shows a small wave with a double peak which is due to the heart beat 2 close contraction and a pause.
Is this right ?

We can’t really see enough of the flow rate but it looks like a large breath before each one so likely not obstructive

But why use such an expensive machine in cpap mode, what a waste