I have done a few tests, and I think I know how to calculate bot uptime. I noticed, if your post is done after 7 PM (forum hours), that posts will be calculated according to the new date, it's 1 day faster than the day of the forum. So, consider to make your posts.
In addition, there are some reasons that your post may not be counted, I think it is about the quality and subject you make. Hope this information is useful to everyone