Haven't tried that actually, I'll give it a shot. Thank you for the in-depth explanation of the feature :-)

The main issue is really that with cellular data enabled all sorts of stuff starts using the megs I do have (which are few), e.g. for updates, checking e-mail, checking weather and what not. I've tried disabling background updates for a ton of apps, but I can still see my megs just disappearing rapidly.

Sadly the carrier doesn't support wifi calling either, so I'm probably just plain out of luck :-/

Bummer, but thanks for the answer none-the-less :-)

I should have mentioned this in my question, sorry. My carrier doesn't support Wi-Fi calling.

I'm sorry my question didn't include this aspect. I realize I need data, however I don't want a full-blown cellular data connection as I have no data plan (and no access to one really), as such it gets way too experience with updates and whatnot.