A kitchen orders ingredients, but it sells dishes. Between the two sit recipes, yields, shelf life, delivery days, minimum order quantities and the weekend's bookings. Most restaurants bridge that gap with a walk-in check and experience, which works until the chef is off, the menu changes or a supplier moves its delivery day.
Restaurant purchasing software records orders and prices well. What it rarely does is say what to order. We build that step: a forecast of covers and dish sales from the POS history, bookings, the calendar and the weather, converted through the recipes into ingredient demand, then into a suggested order for each supplier.