I wouldn't get too hung up about how low down your prolapse is in percentage terms. I'm not quite sure what you mean anyway by 65-70%. Generally, I would suggest you go by way of your symptoms. Some women have large prolapses and are totally unaffected in their day to day lives whereas other women with a small amount of vaginal wall laxity can be quite disabled by their symptoms. Treatment should be tailored to not only the degree of prolapse but also to how much medical intervention an individual requires.
However, if the prolapse is visible and is beginning to protrude out of the vagina, then there is a risk of ulceration/infection and this probably warrants treatment regardless of symptoms.