Building orientation does not affect the natural ventilation. The "Cooling months only, 7days/week" option means that windows may be open 24/7 during the cooling months, but only if the outdoor conditions (temperature and humidity) are favorable. There is not currently an option to restrict the natural ventilation to certain hours of the day. However, note that the amount of window area that is assumed to be open for natural ventilation is a small fraction of the operable window area (which is a user input) because A) operable windows can only open so much, B) occupants are not always home to open windows, and C) some occupants don't open windows even if home.
We have considered allowing more flexibility around natural ventilation inputs in the future.