I asked the wise folks over at www.car-seat.org about whether or not the
top 2 slots on Val's seat can be used for rear-facing. They pointed me
to a transcript of a chat with the director of engineering for the
company who made the seat. He said that all slots can be used for
rear-facing so woo hoo! Val can continue to ride that way in all her
seats for at least 5 more pounds.