Firstly Nina this is nothing to do with taxation. The word gravante, just meand weighing, but all costs weigh, all costs are a burden. It is just 'un modo di dire' in Italian
La soluzione definita prevede che le strategie e le priorità d’intervento, relative agli aspetti di logistica commerciale, vengano concordate tra Supply Chain Commerciale e Mercati, in funzione del livello di servizio ai clienti, delle possibili sinergie operative e dei relativi COSTI GRAVANTI sul conto economico delle aziende"
"The final solution is for the strategies and details of the commercial logistics to be agreed betwen the SCC and Ms on the basis of the standard of service to customers, the operating synergies and the costs (chargeable to the income statements) to companies."
To try and insert some sort "burden" or "weighing" in their is to translate the words instead of the message.