The quoted £500 for a HKG trip is well below the reality. For a junior crew member the extras will include 2 box payments of £320+, overtime after 12:30 hours duty at about £45 per hour (about 4.5 hours), overnight allowance of another £40, and then meal allowances of about £350. The whole trip for a main crew member is worth closer to £1000 than £500.