I asked this question on CC a year ago and my impression form replies was that unweighted was the better number to use to find our match, reach and safety schools. This turned out to be right for us: son got into almost all matches, almost no reaches, and all safeties.
I think that is a good assumption given all the variances in how high schools manage GPA. I would have preferred our high school not translate percentage to letter grade because I had one kid who was notorious for getting a 92 which is a B+ in our district high school and a 3 at UofM when they view the letter.