The SFS is in practice a good idea, as at the very least it will get people who don't like doing up budgets to see where every penny goes. However, I have always found it a little rigid for my own personal reasons, as it is hard to ascertain from it my proper P&L - I find it much easier to have an excel sheet with all DD's etc running down it. You can see on one page where everything goes as opposed to a 10 page document! Another restriction is it doesn't really accomodate people who have P&L's in different currencies.
A rebuild should probably be put in place to match the "living" guidelines, but I can't see it happening anytime soon.