There is a price incentive to use as little as possible. When you do this, you end up with softer shot and less reliable patterns. It's hard to tell on an absolute scale because the wad and powder also play a part in patterning, but it's pretty safe to say that, all else remaining equal, soft shot can open up a pattern ten percent or better. It will also lengthen the shot string. More open patterns aren't necessarily bad.
Wads can vary in cost and performance too.
Wads are made from polyethylene plastic. The problem with recycled poly is that it is harder to control the blend of plastics it contains. This can translate into wads that don't seal quite as well in cold weather. Cold weather makes plastic get harder. You want the wad skirt to remain flexible enough to seal against the walls of the hull and barrel.