Just got off the phone with a Park n Fly rep. After Jan 1, 2019, PNF at SFO is going to only offer valet parking. No more self-park. I have a bunch of Costco vouchers and they state that they are only good for self-park. However, the phone rep said they would have to accept them for valet if that is all they offer. Hopefully that holds true.

I called about this after trying to make a reservation online for over the holidays (starting in Dec, ending in Jan) and the website only offered valet. I was able to make a reservation ending Dec 31 for self-park, using Costco vouchers for each day. Since I won't actually leave the lot until a few days later in Jan, I'll pay the extra days upon exit, also with vouchers.