Ok. Thanks! That makes sense, in a way. What I mean is the manual says like ' Instead of using two or three separate signal cables, it is also possible to connect cables in loop-through mode'. This led the uneducated me to believe that VU+ Ultimo is somehow able to 'split' the signal, and provide full feed from loop-through cable to the second tuner's LNB In.
So I guess no such luck. And gotta get to changing the LNB!