Buon Giorno Storeweb! if you wont find Italian you can hire Lithuanian who has experience working with Italians:)
I specialize in Prestashop development and module creation, configuration. I understood that you are selling baseboards and pavements, but the calculation is not right. Yes? Can you tell me more about it: 1. what's the prestashop? could you send url? 2. how do you calculate the prices? do you use some file, doc or do you handle it manually?
Lets continue over the chat!