Not true. What they failed to find was a Big Mac. Since there isn’t a McDonalds in Luanda, the next best thing is something that can be bought in just about any four or five star hotel - a club sandwhich.
It’s the same with the price of jeans. They don’t compare Wally World denim to the price of Armoni Jeens from a street stall in Ulan Bator, it’s the cost of a pair of 501s.
And based on personal experience, they get the cost of living for their target audience about right. Most oil company executives I know don’t live in mud huts or live on a diet of yams and boiled monkey.