I'm not sure why you only unclip with one foot (you may have a reason mentioned in another post I haven't read), but you should probably practice with both. I have been in a few situations where I've come thisclose to a crash because I couldn't unclip on my usual side (i.e. being on the very edge of a slope with the drop off on the side where I usually unclip, forcing me to unclip on the other to take my weight to that side so I don't tumble down the hill), so practicing with both sides has been really important to me.