Viktor Karlsson Mantel
I frequently get this mixed up as well, and I agree that the example in the rules doesn't really fit the rule statement itself. A simpler way to state the rule might be to say that a figure must be taller than any ledge they're attempting to climb. Which kind of makes sense. So a Height 4 fig could indeed climb up 3 levels (at a cost of 4 MP).
And if he would have a height of 3 he would not br allowed to move up there in your example?