Of course we don't want to pay the clause - it's 38 million in one shot. Marotta loves replenishing payables with more payables. He will look to term out the obligation.
That being said, Roma has every incentive to ask for more.
Using a quick time value of money calculation, spreading that payment over 4 years should mean a fee closer to 45 million, and that doesn't include Roma trying to bend the league champions over a barrel. Roma will want at least 45 million in value or probably even 50 million if we try to do player swaps.
A cleaner option in my mind would be to sell Zaza for straight cash for about 25-30 million, use part of proceeds to buy a cheap striker (Graziano Pelle, who will be a good reserve option ~10MM), and use the remaining to fund the majority of the buyout with while using 18-23 million in cash on hand or through the sales of Asamoah or Pereyra.