If you find you're getting value out of that and enjoying yourself, then feel free. Adding in other content generally doesn't hurt, it's more a question of whether you're enjoying it and (less importantly), whether it's an optimal use of your time. So if you're choosing between: A. 60 minutes of Fluent Forever, or B. 30 minutes of FF + 30 minutes of something else
Try both, see how they go. You'll likely find that one of those is more enjoyable, and that's the one that you should stick with.