Assuming the product will have the shipping method after the reset. How do we know which other products are in that condition? If I have 2,000 products, I will check each one of them? It don't make sense.The product is updated from the seller end.
Our plugin don't update variation was not exit in the first time we import them.
So for example you import this product 1 year ago, the seller after add or remove the variation usa, this change is never gonna appear in your site if you don't reset the product.