Wright, a physicist and technical arms control specialist, said the launch appears to show North Korea can "go considerably farther" than previous efforts. He believes this missile on a standard trajectory would have a range of 10,400 kilometers (close to 6,500 miles) before accounting for the rotation of the Earth, which extends the range of missiles fired from west to east. However, Wright said it's still unclear if North Korea reduced the payload on this new test to get a longer range than the test on July 4.
Earth rotates West to East... Shouldn’t the article read Missiles fired East to West extends the range?
Maybe the tangential velocity adds to the eastward trajectory (while it would subtract from the westward trajectory) having a greater net affect than the actual angular displacement of rotation?
R/ Projection Plane