how to work out a tow car ???

we have been looking at a caravan with a gross weight of 1500kg at a dealers, he asked us the details of our car which is a  mondeo 2010 titanium x manual saloon, he came back with a figure the car will tow of 1573kg and said it would be fine, we have just looked on the car matching and it says with a caravan of 1466kg we would be at 93 % of the cars towing capacity, are the readings from the kerb weight of the car  without passengers ect, we have never had a tourer before and would like an idea of what we can look for weight wise as we need a 4 or 5 berth van, thanks in advance