Your model is a 31" waist and wears a Size 30. The Size 30 according to the chart is a 34" waist, so he sized up 3 inches?
The Size 31 is also a 34' waist, with the only difference is an extra 0.25" in the thigh and identical everywhere else
If i am a true 32" waist, what size should I be wearing? A Size 31 to down size 1 like the model from tagged size?