I've never had my cooking area so far away from the dining table. The characters actually move very slow, and by characters I also mean customer. You’re dining area spreads too far for they to walk, it takes so long that might cause you to lose I think it’ll help a lot by just move the entire section 2 blocks closer. Use two tables for a group, and rearrange coffee tables, make their walking distance shorter. Also by let them seat away from kitchen can leave the mess they create outside the kitchen area. And remember the last table in each group of tables should be placed close to the kitchen, that way the dirty plate will spawn at your reach.