Tvheadend

I have tvheadend setup with a dvb-c tuner and a dvb-s tuner.

I also have oscam with 2 subscription cards (one for dvb-c and one for dvb-s)

I have 2 users in tvheadend/oscam connection, one user locked to dvb-c subscription card and the other locked to dvb-s subscription card.

Now I notice whenever I watch a channel tvheadend/oscam allways check both subscription cards the whole time, one working and the other failing ECM. I guess this is not a big issue and maybe working as intended but I'm a little worried about how EMM will get handled. I don't want it mixing up the cards when writing EMMs !

Usually the codes are not the same on both subsciption cards (same provider) but on one channel I notice that both sub cards work, and in that case only one of the cards was checked from that point on when I continue watching (and it was actually the wrong subscription card in use!!)

What is the correct way to do this, in other tvservers I've used you allways lock your tuner to a spesific softcam connection, but I don't see how this is possible in tvheadend ?