Hours per Week?

For the activities section, is it okay to list your hours per week for junior year (and maybe specify that somewhere?) considering it may have varied from freshman through senior year, and someone might not keep track of EC times for the first two years? Thanks!

From my experience, the form more or less implies that you should provide the average involvement over the time period in which you participated (which, in this case, would be four years). However, it is fine to estimate your hours and some deviation will not harm you; note, however, that this does not mean you should consciously exaggerate your involvement.