It seems unfair and too hard to acquire points after the bonus mode has been acheived. There are two main reasons for that. 1) Too few br points are offered in bonus mode and 2) farmers have to wait at least 2 hours for next task no matter what. Because of this, farmers may lose rank within their coop and the coop may not advance as quickly.
My suggestions are to offer double the BR points once bonus mode has been achieved and if both bonus mode and the special event task have been completed, offer triple the BR points. Also, it would be better if each farmer could continue to accumulate the 200 points for each time the special task is completed during the week. Further, please consider giving options for farmers not have to wait 2 hours or more between tasks. For example, the first 5 or 10 farmers in each coop reaching bonus mode will have no wait time between tasks.