Amazon spent less money than expected on shortening its standard delivery time to one day last quarter — here's how it did it (AMZN)

· Amazon Chief Financial Officer Brian Olsavsky said "efficiency" in its delivery infrastructure helped the company save on shipping costs last quarter.
· Amazon spent less than the $1.5 billion it had expected last quarter in shortening its standard delivery time from two days to a single day, Olsavsky said.
· The increased...