The feature: Include the total count of tweets in each tweet.
The reason I had trouble figuring it out: you seem to need the number before you have it. But somehow, automatically, it seems to figure it out. First you see the incorrect sequence, with missing total counts, then it adjusts itself, adds the counts, and seems to rewrap everything so it just works.
It even works when you get to 10. I assume it will also work when you get to 100, though I haven't tried it.
If you think the counts are wrong, enter a space, anywhere, pause, then delete it. This will cause everything to recalc. After the recalc the numbers should adjust.
Here's a demo of a tweetstorm produced with the new version.
There's a pref that lets you turn the feature off. It's in the Prefix panel. Just clear the checkbox and click OK and the total counts will not be generated, the software will work as in previous versions.