on 1/19, Delta has a 7:30 AM flight from JFK to JAX, and a 9:30 AM flight from LGA to JAX. Both are non-stop, and both cost $188.00. However, the Skymiles required for the 7:30 JFK flight is 4,500, and for the 9:30 LGA flight is 14,500. How do they come up with these figures?