A quick generic question about eagle cad footprints
I think you miss type the size of the element14 footprint size. Any way, the footprint is always larger than the chip in order to make solder easier. You can find in the datasheet the recommended size of the footprint as well as more information about the soldering process : temperature and time exposure for instance. Since it just a recommandation, it may very from one manufacturer to another or from a "footprint designer" to another. 

You just have to be sure that the footprint has the same size as the chip. If you try to do so, the chip may not be well solder and the solder will break due to many causes : vibration, temperature..