Interesting post by Simguru Nick 3 days ago on the EA help forum, in case you missed it:
"My QA team is definitely aware of this issue, and has reproduced it as well. I don't know when this will be fixed, but from what I understand the issue is due to overly complicated tuning, and thus it's not a simple fix. Apparently there are way too many variables involved with determining the final food quality. It seems that there is almost no quality gain from being a high skill chef, but there is a massive quality hit from recipe difficulty.
There's not much more I can say (as that's all I know), but thank you so much to everyone who provided me with info and save files and helped our QA team narrow this one down."
answers.ea.com/t5/The-Sims-4-Bug-Reports/OPEN-DO-Top-level-chefs-in-restaurant-cooking-poor-quality-food/td-p/5661262/page/10
Comments
It was good to read the update from SimGuruNick. Although the issue remains and it sounds an involved issue, it is great that he has written a helpful update to explain the current situation .
http://forums.thesims.com/en_US/discussion/817478/hello-come-and-introduce-yourself
http://tinyurl.com/OneRoomOneWeek
http://tinyurl.com/rosemow
My Showcase thread https://forums.thesims.com/en_US/discussion/948861/rosemow-s-rooms-showcase