Having your star rating go down is not something about which you need be concerned All that happens is that food sells much slower and it affords you time to build up a little stockpile. Once you give customers access to all the chairs the rating goes back up pretty much immediately. Having your counters empty while your food cooks also makes your rating drop.
Closing the door is much worse than turning the chairs. Closing the bakery door has had some seriously adverse effects for some players. Not everyone experiences it, but for some players once the door opens all the food on the counters just disappears. I think some other things have happened as well but can't remember. So TL warns against doing it.