It’s a plug in designed to blend frames, and it has enough options to keep you happy. It’s not just about slowing down or speeding up. You can change frame rates in general, taking 30fps footage and getting a better 24fps output is certainly a great option, this should work for converting any frame rate you require. As far as I know, the amount of frame rate changes you can implement to clip is limitless, given your OK with waiting for a long render to create new frames. The amount of controls given to each keyframe is pretty impressive.