I think that Miles knows another way off the Island and he was telling Ben that with the 3.2 million.
3, 2, 5 zeros
That is also the coordinates that Michael was told to use to leave the island in season 2.
Either that or maybe that is the way to the second Island where Jack, Sawyer and Kate were taken to.
Miles may also know that Michael is Ben's spy.
as for the coordinates that the helicopter followed
305, Maybe Ecko was trying to tell Locke (John 3:05) how to get off the island.
I am so sucked back into Lost, and can't wait for the next episode.