The rest is from items created by the chef from bulk materials for salad, soup, desserts, etc. Once past the entree, you will find the bulk food costs are minimal for these items. The visual appeal and the taste of the food is just as important as quantity. You can serve an 8 oz steak instead of a 10 oz steak. Payroll costs can be reduced by presetting items.
Catering is a seller's market.
A typical hotel requires a written guarantee 24 hours in advance of each function. Hotels generally quote catering prices to meeting planners about one year before the meeting.