I read somewhere that even a version with a timer passed. But don't ask me exactly how and I’m not allowed to write more here about where, otherwise I will get kicked.
Then I will submit the version with the timer/ changeover relay (incl. schematics) and see how it positions itself against Novelan/Zehnder (incl. options box).
The question never occurred to me, since for 153 you also need the energy expert. The aim is to prevent double funding of the acquisition. 431 only subsidizes the consulting service and the inspection, so it should be okay.
Yes, you can combine all of them. However, you are not allowed to use your BAFA eligible amount to pay off a KfW or other funding. Otherwise, it is double funding and you will have to repay the case.