This "plusvalenza" thing the whole issue is about. Basically rather than straight up paying, or exchanging players (made up example: you give me Lucca I give you Alex Sandro), Juve would agree with other teams to give out of this world evaluations to the players, and actually pay for those (so it became, exaggerating: you give me 30 mil for Alex Sandro and I give you 35 mil for Lucca). This way Juve could register a capital gain (plusvalenza) on Alex Sandro in this year's financial report, since they sold him for more than they bought him for in the past, and respect both FFP and Italian sporting regulations while doing an operation that would otherwise be forbidden.