When I learned crochet, I crocheted few garments using the patterns available online. Most of the patterns had constant ease for each size. Then I thought that the ease shlould be proportionate to the size. I found few articles online mentioning the same. But I was not sure whether adding proportionate ease would give same fit for all the sizes and wanted to calculate it mathematically. I wanted a proof. So I did some calculations, and to my surprise the old method of adding same ease would give you the same fit for all the sizes and not the proportionate ease. If you use proportionate ease like 15% or 20% of the chest circumference, then the baby sizes clothes will be tight and the larger sizes clothes will be too loose. I would try to explain this with a diagram. (I have just calculated it theoretically). It would be great if any crochet or knitting designer try this concept and then confirm it practically. It would be really helpful for all the crocheters and knitters.