In my opinion (I read the EN) it is not clear defined how the oxygen support for a system is to be done. there is only "it must guarantee the live support" So if all equipment is O2 certified and the manufacteur can guarantee that the messuring system is save enough and well documented I think there is no problem to get the CE. There are some other system out there with KISS-Style gassupport with CE on the market so why not.
I think the CK can also get the CE when the WOB is in the CE range
Holger