Sriram and Gandalf,
Silver level (American) Foxtrot is distinguished from Bronze level Foxtrot primarily by one factor: Continuity.
The Bronze Foxtrot mostly uses chasse-type figures, where the feet close on the third or fourth step, much like Quickstep. The Silver American Foxtrot looks much more like its International counterpart, Slow Foxtrot, where the feet are continually passing, very seldom executing a chasse action of any kind.
Some people describe them as being different dances altogether. But I don't. I like to mix them all up into one dance, so that I can have the most ideas at my disposal at any given moment.
Still, I can see why one might look at it that way. The style of movement feels quite different, and if you really separate your actions up into two distinct groups like that, it's going to feel like two entirely separate dances. But if you really mix it all up, you hardly notice.
Also, I sometimes keep the two apart with my students, particularly when I'm first introducing them to the silver level continuity action. It's hard enough for them to learn an entirely new type of action... to also burden them with the distinction of one lead vs. another is often overwhelming. So it's often easier to just say, "Don't be intimidated... just imagine that you are learning an entirely different dance!"
Sincerely,
Jonathan Atkinson