i just had my housewarming last weekend, i dun think you need to order for the exact number of pax.. i had about 50 guests, i ordered for 40 pax and had quite a lot of leftovers.. are you sure your house can accomodate so many people? i had to hold two housewarming.. one for relatives and another for friends.. mine is a 5 room hdb, 110sqm and with 50 people it was very cramp..