Hi,
Only the original prices are saved along with products. The discount price is always calculated dynamically from the product price and the discounts configured via the menu System->Discounts.
Which means that you cannot import discounted prices since there is nowhere to save them. In that case, you should import discounts via the import function of phpmyadmin into the hikashop_discount table and specifying the product id in the information of the discount.
Also, note that you can't have more than 1 crossed price per product.