I beleive the reason for the Eastern cruise being less expensive is one fewer port, therefore lower port charges and taxes. That probably is not the only difference. It may be a lot cheaper to park at St. Maarten than Key West, or Grand Cayman or Cozamel. The Magic "parks" in prime locations on the Western cruise (except of course Grand Cayman where everyone anchors off shore). In St. Maarten there appears to be only one pier where we stop on the Dutch side.