When the Losties are banging around in time during th FDW flashes they influence much of what happens in the future. Thinking along those lines i'm wondering IF the FST is showing what would happen if 815 had never crashed, then the flashes would never have happened.
One in particular i think may have been more important than we thought at the time. Sawyer holding the rope at the site of the (at that time) undug well. It is possible that they may have been farther in the past than we could have ever imagined, and what IF that rope of sawyers was the only reason the well was dug, and just possibly the well being dug down to the FDW area created smokey and a reason for Jacob to be a caretaker of sorts?
i dunno, i have a few theories a week but i only like to post the fun/good ones.
this one seemed fun, so i wanted to see what others thought of my convoluted mind.