I just used the H422 code to book a trip. I was very absent-minded and indended to book BOS>NYP but accidentally booked NYP>BOS. I called up reservations w/in 5 minutes, intending to give a sob story, but she just checked and said "I don't see anything about the ticket that suggests its not refundable," and credited me the original purchase, and rebooked me on the BOS>NYP train.

YMMV, of course, but I was quite relieved.