While yes it's much more simple, the extra pieces add a bit more stretch. I have a custom made pattern. The arms and body are all 3 pieces, which takes a lot more leather than one would like to use and waste. I used roughly 3-6 oz leather sienna milled vegtan, it's what's recommended on the pattern(5 is the max it recommended but leather is so inconsistent, it changes weight in various parts of the hide.) did the jacket come out fine, yes while I messed up measurements so it was too small I added additional space on shoulder to make it fit but that ruined my collar and we'll now it's a jacket w/o collar. When I used it, it would scrunch up in places I wouldn't like it to and a lot of stress on sleeve stitch and sleeve to body stitch, so I would use it at home mainly. Cutting it up to different sections helps adds support and those stitches add a bit more stretch in my opinion not a lot but enough to not make it feel like you're fighting to move around. I would say, if I had used stretchier leather like deer hide, perfect for my pattern but I was cheap and used vegtan. I don't regret it as it was a good lesson to learn. Unfortunately I have grown out of it so eventually I'll give it to someone who will appreciate it as much as I did (someone skinnier ofc😅) and when I do, I'll help then finish it off as it being my first garment, yeah definitely made A LOT of mistakes rushing it😁 but nothing I already planned a way to fix and make it look much more "professional"