I often wonder when a manufacturer offers different sizes, how can they be sure to stay "accurate" when creating the different sized patterns? Or is there such a thing as accurate grading? Let me elaborate. Say, if a repro maker is able to get hold of a jacket in different sizes, and make exact copies of them, then all the jackets of these sizes are accurate, this is the benchmark, set. However, it's quite hard to obtain more than one or two sizes of Aero 15142, so we'll have to grade it ourselves in a proportionate grading approach that we think should preserve the overall, or certain, key proportion of the particular contract. Granted, when grading a men's jacket, the chest and belly area fluctuates much more prominently than shoulder width or arm length. Therefore, a size 50 Aero 15142 would have just slightly wider shoulder and fatter arms, but much wider body. So my question is, in clothes making time eternal, the principle of grading has never changed because the way our body grows or lose weight hasn't changed, men always gains weight at the gut and women gains weight at the hip etc, and your arms don't suddenly get longer or shorter. Then the sense of "accuracy" really should not be judged on the these aspects of the pattern right? In other words, say arbitrarily, a size 44 Aero 15142 is accurate, would a size 50 Aero 15142 also accurate? I'd say the answer is, as long as certain key pattern details remains the same, it is accurate, for example the sleeve cap height and the way the sleeves tapers and the body tapers, also, the shoulder slope. Note, I'm only taking about the "sloper" here, not the local details, since say the pocket size wouldn't have to change just because you are two size larger or smaller than the other. The pretext here obviously is that across all the sizes, all the local details remain the same (same epaulettes, same pocket shape, same zippers).