Variants prices per weight

-- HikaShop version -- : 2.5.0

Hi everyone

I have a question...

My costumer sells fishes. So i display prices per weight and sell products depeding of the weight.
So, for each of my products, i added a price for 1kg and i created variants for the differents weights :
800g / 1k / 1.5k
In the variants, i fill the weight field and let the price "blank" thinking it was calculating automatically depending of the weight selected...

But when i'm on the product page, the price changes depending the unit price and not the weight price, so for 1kg the price is ok (19.90 € / k and 19.90 € per unit) but when i select 1.5kg for exemple, the price depends of the unit price and not the weight price (13.27 € / k and still 19.90 € per unit - it should still be 19.90 / k and 29.85 € per unit)

Is there a way to make the price changes depending the weight and not the unit price ? Or do i have to set up each prices manually ?

Thank you for your help !

Too bad.... Wondering if hikashop is really made for me...