I really wouldn't say 2 lame workouts (btw, I don't consider 20 minutes of light jogging to be lame

) EQUAL one high intensity workout.
That said, its definitely better than NO WORKOUT...and you will still see results provided your diet is in check.
I guess everyone's different, I've done HIIT, intervals, etc. but for me nothing drops the pounds like going for the longer runs (1 hr or better). IMHO, get to know what works for your body and follow that.