I just recently purchased a Soma Lyra8, only have had it for a few days. So I am pulling all the levers to listen what happens. From your explanation, yes. The “35>56 78>12” switch in UP couples “Banks 1 to 4 ” to “Banks 5 to 8”, whereas when the “35>56 78>12” switch in DOWN, only the four switches (“34|LFO FB CV”, “12|LFO FB CV”, “78|LFO FB CV” and “56|LFO FB CV”) control the FM modulation (now “Banks 1 to 4” are independently modulated from “Banks 5 to 8”).
Just by listening there appears to be some other coupling, I can’t quite place my finger on, I suspect some of that magic cross-talk in the circuit, Vlad is talking about.
I am happy to be corrected if I got this wrong.