Considering subcategories as priority

Hi, I’ve recently added subcagetories to some of my categories. And I noticed, that your plugin doesn’t consider subcategories as a priority for posts. It randomly shows absolutely all posts from the same category (I use “Search similar posts by using only categories” option in your settings).

I know, that I can improve the results of related posts, by turning on “Using categories and tags” option, but I don’t use any tags on my website. And many other website owners don’t use them too.

For example, in YARPP you can choose to have a category as a priority, or you can choose to show posts with at least 2 same categories – it helps to show related posts, that are only in needed subcategories.

So can you add an option to consider subcategories as a priority? (if a specific post IS in a subcategory, of course). That would be great!