360 miles is the imaginary cutoff between driving and flying. Distances are rounded to the nearest 10 miles so it also depends on which side of the 360 the actual distance is rounded from.
If the distance is 358 and rounded to 360 the cost to recruit is much less than if the distance is 362 and rounded down to 360. So there be some great variances at 360. Up to $300 difference even for the same mileage.