There is good news and bad news for the answer to this question:
The bad news: Unfortunately, the specific answer to that question has never been fully released by Chris and Melanie, and probably won't be, since it is the proprietary information that holds business value for the Dramatica software program. (If you look around on the forum, you'll see this question is asked in a number of ways, and this has always been the answer.)
The good news: In order to use Dramatica to improve your writing, you don't really need to know how it chose that. You only need to know that it did choose that.
Note (I doubt I say this right.): Understanding that the mixing up of Theme and Plot is a result of the inequity in a story, and the unraveling of that twisting is part of the problem-solving process of the Storymind represented by that particular Storyform in an attempt to find the actual answer to the inequity can be helpful, for some people. For others, that sentences is a bunch of noise.
Note 2: I spent a whole lot of time trying to figure it out (~5 years in total), and I finally think I have a decent idea which may still be incorrect. In the end, though, I haven't used one iota of any assumed understanding of the Process that generates the PSR in my writing. However, I have consistently used the Result of the PSR itself.