I think we talked somewhat about this in another thread... or maybe that wasn't you

I honestly can't recall (chalk that up to brain fog! LOL)
Which Opus is yours, a 360, a 482? You need to look up the expected leak rate at your pressure, it should be contained in one of the product literature or details on the F&P site.
Do I recall you have a ResMed machine? You need to set the mask type to standard when using the Opus. But this still does not give you the true picture of leak, if I recall CrohnieToo's posts on the subject. Even at 'standard' setting ResMed subtracts a certain minimum expected leak rate, then still only shows you 95th percentile for the night.
I believe CrohnieToo had to call or email ResMed to find out what the machine assumes as leak at her pressure.
Once you know the expected leak of the Opus at your pressure, and know what amount of leak the ResMed is assuming (so it shows you what is left), you can see how much leak you're experiencing above and beyond what is expected from your mask.
For an example (and I am making these figures up! This is just to illustrate the math).
1. Let's pretend your model Opus is expected to exhaust at .5 liters per second at a pressure of 15.
2. Let's pretend your ResMed on Standard Mask setting expects .2 liters per second exhaust from any mask, so it subtracts that amount from whatever it will display to you on the screen at 95th percentile.
3. Let's pretend your ResMed on Standard Mask setting displays .6 liters per second at 95th percentile.
The math is this: ResMed assumption + ResMed display = 95th percentile of mask leak. In the pretend example we have .2 + .6 for a figure of .8 liters per second recorded by the machine at 95% or less for the night.
Since we had pretended the Opus is expected to leak at .5 liters per second, we see that you are .3 liters per second over and above what is expected from the mask. That would be a significant leak and probably the cause for the increase in restless sleep and higher AHI.
Of course I must reiterate these are pretend figures, I do not know what the actual figures are for your machine's assumption, your mask, or what your display shows. You need to find out the real figures so you can do the math.
(I don't use a ResMed, I have a Respironics and they handle this differently, so if I have mis-remembered about ResMed someone PLEASE CORRECT ME and provide the right information! Thanks!)
Blessings,
--pseudonym