Yea factorissimo buildings don't get power when built in the lower floor. But on ground floor it works. Sometimes requires reconnecting the power poles after a warp.
There's also a problem in factorissimo that it doesn't detect the surfaces properly. When picking up a factorissimo building you can't place it anymore as it does some checks for surface name. I disabled those in their lua and now I can place them again.
So, a bit messy but works good enough for me.
I have also tried to increase the size via floor.levels as you mentioned. Doesn't seem to work on existing saves - or at least I couldn't get it to do anything.