Chateau, I can't figure this out. If the flight was on time (which it is possible it was late, and we ssume it took a hour to go from the plane to the boats thats puts us at around 10am. WHich is significantly off.
I have to assume that not only was there a limit on how often the boats departed, but that they didn't start until roughly your time stamp of Eric & Danielle and the Oswald & Danny.
Which does actually make some sense, since in the clips they go to great lengths to joke about how long Teri & Ian must be looking in the hills for the clue box in the wrong direction. Which does play into Ian admitting that they spent about 40 minutes in the wrong area. Perhaps he is saving face, and it was a little longer, say closr to an hour.
And lets assume that the first flight did in fact arrive leave and arrive late (which is possible and would explain why Amber that it was possible that they might catch up to the first pack, I mean a three hour gap in the 2cd half of the race is usually fairly solid to the Pit Stop.
This could mean that they might have arrived say at closer to 10, then 9 with a delay. Spent about an hour getting to teh dock area, gives time for Ian & Teri to be lost close to an hour, and bunching point with the times that the boats start hours of operation, would also explain how E & D and O & D know that Teri & Ian have lost a significant amount of time. They could get to the docks just after the other teams left. Which would be fairly close to the arrival time of the 2cd flight. This also helps support why Teri is so worried about how long she is taking doing the roadblock.
Flights lands close to Noon, gives them an hour to get to the docks gives times for roughly a 30 minute wait for Uchenna & Joyce 2cd boat. To do the tasks and get to the Pit Stop aroung your 1:30-2:00 calculation.
Its the only thing I can think of that makes any sense.