We don't give out rough estimates if we can avoid it - devs get sick, sometimes the writing is quick but the scenes take longer to do than we thought, sometimes images take me longer to do than I planned, sometimes one of us has to spend a few days doing work that isn't related to actual game development (taxes, ads, merch development, setting up a con table, etc), power outages, computers break, revisions, etc..
We thought the game would be done this time last year and Jessie's chapter 4 was 2 times more image dense than the next longest chapter we'd done. We could certainly plan better but people have almost universally said they prefer us to add stuff when we think it makes the game better, so we do.
We have a convention table at Anthrocon this year, it should be done before that or we won't be able to shill the game on steam at our table :V