Every bounty has a rule and the rules must be followed strictly to allow the person to get a stake but I think it would be a good idea that bounty managers should award half stake to anyone that reaches half of the post for the week.
A few manager do that, but mostly manager does not tolerate people who do not complete his target post within 1 week. For him, they are too lazy to write. In altcoin sign camp, I only see a maximum of 20 posts a week, but currently only 15 are the most. I don't know what they did, so making 15 posts in 1 week was so difficult, even though if they made 3 posts in a day it would be done in 5 days, that must be easy.