I'm by no means an expert (found this site a few days ago, this is my 2nd post and really the 1st time discussing BJ in depth with other people, done some research on the internet but never read a BJ book, never done any sim analysis, never heard of floating advantage) so I apologize if I say something idiotic.
Let's say you're playing an X deck game with Y decks left and TC = 0. It seems at this point you're essentially playing a Y deck game. If this is the case then (at least for TC = 0):
1. Floating advantage (if I'm grasping this right) = Y deck BS HE - X deck BS HE
2. You should switch to Y deck BS (ex. 6D shoe with 2 decks left, double on 9 vs. 2)
3. You should switch to Y deck BS indices (ex. same situation as #2, insurance index of 2.4)
4. If you're Kelly betting the FA is not going to change your bet, at least not a whole unit. Intuitively guessing, the only situations where the FA is close to 0.5% is at the end of an 8D 85% pen game or 2D 65-70% pen game. Obviously, I could be wrong about this.
It seems an "FA adjustment" (#2-4 above) is actually a lot more valuable on DD than shoe games because for DD the FA is bigger and BS changes and index changes are more drastic (ex. DD half way through, double on 8 vs. 5 and 6, insurance index of 1.4).