Single (once) Rovers are pretty simple, but when you get into daily or weekly Rovers, there's a bit more going on.
Let me try to explain.
The architecture of the app is "Rover contains Search(es), Search(es) contain Torrents". When you do a single (once) search, you don't even see the Search part because there's only one and it's the same search text as what's on the Rover, so the search is completely hidden. But when you do a daily or weekly search, the Rover can contain multiple Searches (eg. S01E01, S01E02, etc...). The "Starts With" allows you to tell the Rover you're creating where to start searching (eg. Season 10 Episode 1). If you edit a Rover, however, the searches are already added, and you can't pick a new starting point. That's why those boxes are greyed out.
If you want to add more Searches to a Rover, select the Rover, and you can use the button toolbar in the middle of the screen to get previous season, previous episode, next episode, and next season. It'll add whatever comes before or after based on the currently selected Search.
NOTE: The middle toolbar will only be visible when you select a daily or weekly Rover. If you select a single (once) Rover, it's hidden because it doesn't do anything.
Back to your question about the "Starts With" boxes. Would it be less confusing if they were hidden in the case of a Rover edit? I can certainly hide them...