Hi,
The "product_sort_price" choice of the "ordering field" is what I would recommend.
Note that this field is set by HikaShop each time to save a product in the backend interface.
If you import products via CSV, or a script, or modify the prices via the database or a mass action, the code to (re)calculate that product_sort_price won't be called.
That could explain why it doesn't work properly for some of your products.
An alternative to this would be to use the "sort by price" filter, and add the parameter of the filter in the URL of the page accessing the listing. But that's kind of a trick. It would be better to use the product_sort_price which is meant for that.