Mistranslation or basic Japanese I'm not aware of

[Jericho Desu]

This is a simple problem I guess, however I can't find anything on google in regards to this.

駅から港まで、路線バスが、一時間に三本ずつ走ってい る。

Was translated as "Twice every hour, a bus made the trip from the station to the port."

Now, I've been racking my brain on this for a few days now, but I still don't understand why it's twice every hour and not three times. Is it because a trip from the station to the port counts as one time, then the same bus comes back to the station to make another trip to the port making it twice? If so I still am not sure why it's 三本ずつ.
If there is someone who can clear up my confusion I would greatly appreciate it.

 

[Toritoribe]

It's just a typo or mistranslation. It must be 一時間に二本ずつ (when "twice every hour" is correct) or "three times every hour" (when 一時間に三本ずつ is correct).

 

[Jericho Desu]

Oh thank god, I thought I was missing out on something really basic!
Thank you Toritoribe for rescuing me once again!