I haven't read the book.
Firstly, the agents were Japanese. From WP's page for the film:
In the present day, the novelist notes the parallels between the two stories: the orangutan was Pi's mother, the zebra was the sailor, the hyena was the cook, and Richard Parker, the tiger, was Pi himself. Pi asks him which story the writer prefers, and the writer chooses the one with the tiger because it "is the better story", to which Pi responds, "And so it goes with God". Glancing at a copy of the insurance report, the writer sees the agents wrote that Pi somehow survived 227 days at sea with a tiger: the insurance agents had also chosen the more fantastic story.
WP's page for the novel:
After giving all the relevant information, Pi asks which of the two stories they prefer. Since the officials cannot prove which story is true and neither is relevant to the reasons behind the shipwreck, they choose the story with the animals. Pi thanks them and says, "and so it goes with God."
So the Japanese agents did not use the true story (and similarly, the writer didn't prefer it either) which is essentially the whole point of the tale. The line "and so it goes with God." suggests that, just as the agents (and the writer) prefer the sweet story of the boy and the Royal Bengal Tiger to that of the once-innocent boy and the murderous cook, so too does humanity which prefers the comfortable cloak of religion to the harsh realities of life (or the lonely desolation of atheism, if you like). Of course, this is not what Pi (and presumably, Martel) is trying to convey as he tells the writer right at the beginning that the story will make him believe in God.