Checkout duplicates original price

I don't know how that would happen. Would it be possible to have a back end access to your website to check your settings ?

You can use our contact form: www.hikashop.com/en/support/contact-us.html

Problem is fixed on your website and the correction will be added in next release of hikashop.
We changed the code:
echo $this->currencyHelper->format($price->price_value_without_discount_with_tax,$price->price_currency_id);

to:
if($this->params->get('price_with_tax')){
echo $this->currencyHelper->format($price->price_value_without_discount_with_tax,$price->price_currency_id);
}

in the file listing_price of the view checkout via the menu Display->Views.