Hi,
We found out the hard way that there's a problem with calculation of discounts when a product has variants with a manually set price (a different one). The discount will then be applied twice upon adding the article to the shopping cart (although the listing price is correctly shown with the discount applied once). When we removed the (accidentally set) price in the chosen variant, the correct price with only one discount applied is shown (in the cart).
Background info: because of a tax change we exported the whole database, changed the prices without vat, and imported the database again. Some of the variants ended up having a different price (a bit higher) than the main article.
We use Hikashop 2.0.0 on Joomla 2.5.8
We are now removing these all the variant prices, because our variants actually don't have different prices, but I can imagine other shops DO use this...
Keep up the good work!
MF