The weekend is the business. Saturday and Sunday lunch can produce more than the five days around them, so staffing, ordering and preparation all have to be sized for two services rather than for an average.
Turning tables is the whole peak. Ninety minutes against two hours changes how many parties are seated on a Sunday, and knowing the real average is what makes a queue manageable rather than infuriating.
Every small dish has a cost. Forty items at similar prices hide very different margins, and without costing each one a restaurant cannot tell which trolley favourite is quietly subsidising the rest.
Steamers set the pace. The kitchen's output is limited by how many baskets can be going at once, so a menu that adds another steamed item is a capacity decision rather than a culinary one.