In his video diary just posted online by CBS, Phil tells us that the first teams were due at the pit stop by 12:30 p.m. in the afternoon, as he and his crew didn't get there coming direct on their flight from the airport until 12:10.
The second flight didn't land until 1:47 p.m., according to the chiron graphic information during the episode. That flight delay clearly changed the dynamic of the leg, because instead of being 90 minutes ahead, the "leading flight" was several hours behind.