When I bought my first Bernina 15 years ago, that is what they told me to always do. I sometimes don't remember when changing thread on my Featherweight; but my Bernina is always unthreaded correctly. His other tip on always threading the needle with the presser foot up is a tip I need to remember. I think I can see the eye of the needle better with the presser food down. I wait until I am at the needle threading stage to lower the presser foot. Since the thread went through the tension disks with the foot up; hopefully my lowering the presser foot when I do is OK.