How much does my school's admissions history impact my admissions chances?

@RustyTrowel what is the issue with my current list? I know that I have 4 reaches, but Penn State (I’m in state) and even Rochester are safeties (I was offered 2 separate merit scholarships by Rochester, so I really doubt they would reject me). I’m almost positive I will get into Lehigh; naviance shows that literally every student near me on the scattargram was accepted, and I showed a lot of demonstrated interest. I’m reluctant to add more schools because I think that my list is sufficient, though I was considering adding Pitt. I’d appreciate it if you could explain to me why I need more schools. Do you not think Penn State is a safety? I heard that they admit purely by numbers, and my stats are well above their averages.