To rightly judge someone’s time commitment in an extra curricular activity, one should multiply the intensity (hours per week) with the length of the commitments (number of weeks or months). However, almost nobody does that.
Instead, people tend to look at the number which they’ll think give the best impression of your time commitment: hours per week.
If you can choose between two equal extra curricular opportunities of which one has longer duration and the other higher intensity, choose for intensity. This will most likely impress more on your cv.