Correct. The payout itself doesn't create HBD, but it does put it into circulation. HBD within DHF doesn't count toward the haircut calculation, but once paid out it does.
The DHF receives newly-created HBD from the blockchain every hour (inflation), and some of the HIVE in DHF is converted into HBD every day.
thanks for the clarification, interesting how this all works together, lots of pieces.