The writers did not mess up the time travel thing when Jin traveled with the Losties through time while the helicopter didn't. Both Jin and the helicopter WERE outside the radius of the island when it moved. Jin was floating in the ocean for a while in 2004 until he floated into the window left behind by the moved island. He then appeared in the time that Sawyer and co. were in, which is the same time he would have been in had he stayed on the island when it first moved. Conversely, the Oceanic 6 did not pass through that window in 2004 after the helicopter crashed, but were rescued by Penny. They returned and DID pass through that window in 2007 while on ajira 316. Jack, Kate, Hurley, and Sayid then also appeared in the time that Sawyer and co. were in, which is the same time they would have been in had THEY stayed on the island when it first moved (three years after Ben turned the wheel was both the time the Oceanic 6 took to return to the window over the Pacific and the time Sawyer and co spent trveling through time/staying in Dharma times).