So I asked TK on twitter, they said it was possible to mix carriers. Called the Elite hotline today, they said the same.
I will give the sales office a call tomorrow and see what they have to say about it.
Edit/update: Called the hotline again: they say that it's not possible to mix carriers. TK customer service, gotta love it..
Last edited by Granite64; Aug 7, 2018 at 3:00 pm