Flaps 40 Degrees

This is a great group and I'd like to ask another question that's been burning me. I rent a 172N which has the capability of 40 degrees of flaps. My instructor says, depending on wind conditions, I should use 40 degrees every chance I get. It allows me to slow the plane as much as possible before touching down. I always seem to have a harder time landing with 40 degrees. Either I will bounce a little (I think because of the steep descent) or balloon with a little too much back pressure in the flare. After doing a little research on the web, I found out that Cessna reduced the flap range on the next model 172P to 30 degrees max. They said it was to add a little more to the max takeoff weight. I have read that there were several accidents during go arounds because the 172N barely climbs with 40 degrees and you have to retract to 20 degrees immediately during a go around. Anyways, my instructor still says use 40 if wind conditions permit. I find I make smoother landings with 20 degrees and don't have to worry about flap adjustments if a go around is called for. Does anyone have an opinion on this?