Do these sentenes have the same meaning?

Question

1. The flight to LA is at 7:30 A.M. There after every hour at 30 minutes past the hour.

2. The flight to LA is at 7:30 A.M. There after every hour 30 minutes past the hour.

3. The flight to LA is at 7:30 A.M. There after every 30 minutes past the hour.

4. The flight to LA is at 7:30 A.M. There after every hour at 30 minutes on the hour.

5. The flight to LA is at 7:30 A.M. There after every hour 30 minutes on the hour.

6. The flight to LA is at 7:30 A.M. There after every 30 minutes on the hour.

Answer 1

yeah i believe so.

Answer 2

yea

Answer 3

ya.

Answer 4

4-6 are crazy talk.

1-3 are fine.

Answer 5

Who cares?!

Answer 6

No, not really, use #3.

Answer 7

No. For example, 6 makes no sense. There is no "on the hour" every 30 minutes. 5 would mean the flight is every hour and 30 minutes, yet is still somehow on the hour, which is impossible. 4 says "at 30 minutes on the hour", which makes no sense. On the hour means on the hour.

1, 2, and 3 mean the same thing.1 is the clearest. 3 is the most confusing.