Grassblades has a "finished" outline. I'm putting "finished" in quotes, because what that means is that I've got a beginning, a middle and an end, and I've got the most important characters and when they're supposed to enter and exit the story - but that's it. I've got a LOT of air and vagueness in my outline, because if I had everything set in stone right now, I know my brain would get bored and wander off and do something else. And then I'd never finish anything.
So. I know the main arc of the story, I know what goes in the middle, and I know where everybody is headed. Beyond that, I've got a LOT of leeway in adding and subtracting things.
For example, when I wrote my outline, the trio of people following Masahiro didn't have NEARLY as much screentime as they are scheduled for now. I got to the end of storyboarding part 2 and realised that if I only gave them as much to do as my current outline said, people would forget all about them before they had time to enter the story again, and their actions wouldn't have nearly as much impact. So I added scenes with them in the current (and later) chapters. Same goes for the old lady Watanabe who turned up in part 2 - he was going to be a one-time thing, but people liked her so much that it made me go over my outline again - and I realised that I could bring her back in certain chapters later on.
Most of my edits have been to add stuff - more scenes with existing characters, mainly, to make the story flow better - but I have also axed a few things. Lady Watanabe used to have a husband, for example, and he used to be the one in charge of the palace (my online has "Lord/Lady Watanabe" pencilled in), but I think she works better on her own. There's a scene that would have been in part 5 that got axed in favour of moving another scene forward and to avoid similarities with part 1, etc. There's yet another scene in what would have been part 7 that I've removed because it isn't really necessary, etc.
TL;DR - yes.
I try to make sure I know my ending before I start adding too much stuff to my outline. That way, I know where the story is supposed to be heading, so it's easier to avoid adding subplots that go nowhere, or characters who don't add anything to the story. It's also easier to foreshadow later events, and work on building character arcs.