If I put in a suggestion or bug or whatever and a week later figure out a fix and post that, the forum is automatically merging that with my previous post if no one else has responded. This is a problem for two reasons. One, it doesn't update the last post time when this happens, so unless you click on the post itself, it looks like there has been no activity. Two, because it is retaining the original post timestamp, I can't edit the "changes" I just made like I could on a new post. 

Posts are automatically merged if within a certain time period. That time period maybe adjusted as we see necessary, but otherwise it is there to prevent post spamming and unnecessary bumping of threads.

I had two posts merged that were a week apart. It's really that long of a window?

We've tweaked the times a bit to address some of your concerns.