It could also be referring to one hour there, one hour back.
One hour is equal to two hours, which means it would indeed take six hours.
Eastern · Smoke Painted
The story feels very underwhelming; most interactions feel unrealistic. Additionally, the English not being good just adds to the incongruity of the book. If the author really wants to improve, he/she should picture his/her own interactions with people and ponder if the ones present in the book feel normal. The MC also heavily lacks initiative/focus, even after understanding his ability somewhat and how to progress it. Anyways, good luck improving.
Urban · NanaiSensei
Pornographic Content Hate or bullying Release of personal info Violence Spam Other
Webnovel 
It could also be referring to one hour there, one hour back.
One hour is equal to two hours, which means it would indeed take six hours.
Immortality: Raising an Ant Queen to Cultivate by increasing stat points
Eastern · Smoke Painted