The LOST schedule is confusing but let me summarize TV Guide for you.
April 24 -- season 4, episode 9 -- the first post strike episode (10pm)
May 1 -- season 4, episode 10 (10pm)
May 8 -- season 4, episode 11 (10pm)
May 15 -- season 4, the finale part 1 -- one hour (10pm)
May 29 -- season 4, the finale part 2 -- which will be 2 hours long. (9pm)
The good news is we get an extra hour of LOST this season. The bad news is there is no LOST on May 22 -- because they need the slot for a two hour Grey's Anatomy finale which airs after the Ugly Betty finale. What I cannot wrap my mind around is why you would CALL the final three hours a season finale, but air the first hour two weeks before the second two hours. I guess they are all closely connected -- and we will see how it fits together when it airs-- but where is the harm in just calling it episode 12, 13, and 14 but titling them X part one, X part 2, and X part 3?
But the point here is they negotiated an extra hour -- which in a 13 episode season is kind of a lot.