I called USC to ask why I hadn't gotten a fee waiver, and they said they hadn't sent them all out yet. I got one the next week. I didn't have to give my name or anything. If your numbers are reasonably within the range that they've sent waivers to, I don't think it could hurt your admissions chances to call and talk to someone. Honestly, the admissions people I've talked to seem nice and understanding. At least this early in the season...