In my opinion DHF is a living document (as we have learned) and must updated regularly. Your DHF should be a collection of the objective evidence that demonstrates you’re following 820.30. and every document in the DHF must be updated as you go in your design. If you’re lined up for an inspection, you could get into trouble with FDA if it’s not updated. They expect all changes to be assessed from a design control perspective.
So, keep your DHF updated from the beginning of the project if you want a better chance of getting through your inspection unscathed!