Apparently the upholsters are able to order the near-matching leather with the perforation from leather suppliers. Two things to consider the space between perforations (in our case it is about 4-5 mm) and the direction of the perforations (in our case it is not parallel to the seat sides but diagonal. Therefore they have to order a larger piece to rotate the same and stitch it. Just some detail.
My upholster quoted me $400 - $200 for leather material (perforated) and $200 for labor. This is just for the bottom cushion. I have not gone for it. Will find another way. I only have a small hole (probably caused by a key dangling from PO's pocket...