I ended up booking my 13 day parking reservation at PnF using the Costco vouchers. I had made a reservation up until Dec 31 online using the vouchers, and called in to have them add a second reservation extending it to Jan 4. When we arrived, the self-park lot was full, so ended up in valet. No issues, and service was very friendly. I asked the attendant when leaving about them switching to valet-only and she didn't seem to know anything about it, so maybe I got bad info from rep on phone earlier. I haven't tried making any new reservations yet.