Why Would Apnea increase with a different mask

Hello I have over 5400 hours with good success on Resmed Auto25. Pressure in 10 out 7. My average pressure over the past year has been 13cm and the average AI about 0.4 and AHI around 9. I have been feeling well rested over the past year. I have a Phillips fit life mask - the one that covers your entire face, including my eyes. Last week I developed some allergic reaction which caused a skin reddening and itching. Since the mask could have been a source of the problem I purchased a Resmed Quattro FX full face mask. Always thought it would be good to have a backup mask anyway. The mask was not causing the allergic reaction.
I am able to manage the comfort with the Quattro and the leaks are minimal. Trouble is the Apnea index has jumped from .4 to 4.0, and the AHI from 9 to 19. Of course a consequence is back to the old feeling tired days. For the past couple of nights I have worn the Quattro for the first half of the night and then switched to the fit life. Taking a look at the data you can see the difference like night and day with respect to the apneas. Everything else looks the same except for the constant rate of leakage which is very,very low with the fit life and higher with the quattro (but steady and no big leaks at all) Leakage is not an issue. The quattro seems to be expelling air at a much higher rate than the fit life. The machine is set on the same setting for a full mask, per manufacturer's instruction.

I am at a loss for an explanation. Medigas personal are of no help. I would really like to be able to use this mask. Any ideas or thoughts as to what could be wrong. Everything I can think of is identical except for the mask, one gives great results and the other not.

thanks