The idea is to keep it a double fraim base. If you split it you will degrade the fraim effects of decoupling. If you did it, which I am sure is possible you would need different spikes for one of the levels.
If you can afford a 2nd fraim base it would be better sounding and look better too. Used examples will be at dealers. I managed to get some used fraim shelves from Tom Tom audio.
If not speak to a dealer and see if they can get the alternative spikes that you need to split the stack.
With a quality system you have I would definitely invest in the 2nd Fraim base.
I started off with one Fraim stack and had my other components on a different hifi rack. I ended up spending around £4000 on the Fraim. And most of it is used. I have two Fraim bases and an additional 8 shelves. Would cost me around £7000 new.