Hey! I'm the author, and you're correct. Thank you for your feedback on this. What I wrote is mistaken on that point, and I will adjust it for something more accurate. I've obviously tested all these coinjoin implementations (Whirlpool, JoinMarket and Wasabi) for a few years but I am the least familiar with JoinMarket at the moment.

entirely removing the need for a change output.

Would you have more resources on that point? I'd like to read up more on it. Thanks!