With the smaller player cap needed for cross-platform worlds, this presents a conundrum for world-builders. For a hangout map to be joinable, you would want to set the player cap high. But the hard cap being double the soft cap is not performant or will break a world's assumptions about player numbers.
Why not just have one set limit, and no hard/soft cap separation? The dual behavior is rather confusing and unclear, and really limits how to handle Quest worlds.