Hi,
I'm not sure what you mean by 4 fields ?
If you want several quantity fields for one product there is one way:
You want to create a characteristic with 4 values via Products>Characteristics.
Then add the characteristic to your product, and under the "variants" tab of the product, add the 4 variants corresponding to the 4 values of the characteristic.
Then, configure the "characteristic selection method" setting of the HikaShop configuration to "list" and the "Add to cart on listings" setting to "global".
That will display a quantity field for each variant of the product.