it would seem that only the first post will bump it, since every subsequent post that is still in the 36-hour window will have up to 6 previous posts in the 7-day window... so no bump?
According to What Theymos has said, if you post in a thread every day, 36 hours after your first post, your contribution in thread's bump score becomes zero and will be zero forever.
Here is an example.
GeoCoin is now in
page 5 of "Announcements (Altcoins)" board. So its bump score is zero however
weifa has posted in that thread today. This user has earned 21 merits in the past 365 days. But his contribution in thread's bump score is zero. Because he has made another post on that thread three days ago.