Dlaczego past simple, a nie perfect?

When my next-door neighbour Alex came back from his first term at university, he had changed completely. He had grown his hair long, and, when I saw him, he was wearing baggy cotton clothes instead of the cool clothes he had worn before. He looked like a hippy! When I asked him about his new look, he told me that he had been to a meeting about the environment when he arrived at university, and after a few weeks he had joined Greenpeace. Now he says he's an eco-activist!

Czy ktoś mi może pomóc pojąć dlaczego w przedostatnim zdaniu ma być arrived zamiast had arrived? (tak jest w kluczu) Ogólnie bardzo lubię gramatykę, ale past perfect to moja zmora. Jest to dla mnie nielogiczne, bo skoro w całym przedostatnim zdaniu mówimy o "zaprzeszłości", to dlaczego użyto tam czasu past simple? HELP
P.S. Zadanie z podręcznika na poziomie B1+, temat to past perfect oczywiście.

Może też być 'had arrived', nie ma znaczenia. Następstwo czasów w mowie zależnej zostało wyrażone w zdaniu głównym (he had been to a meeting about ...).

W angielskim tak jak w polskim: czasami jedna rzecz można powiedzieć na wiele sposobów, a znaczenie jest takie samo.

A no właśnie, skoro założymy, że Alex powiedział "I went to a meeting when I had arrived at university" (bo zakładam, że tak musiał powiedzieć?), to dlaczego w mowie zależnej mamy tutaj arrived? Past simple zamienia się na past perfect, ale czas past perfect powinien chyba zostać w takiej samej formie (?)

Nie, w takiej sytuacji nikt nie uzyje past perfect, bo jasna jest sekwencja wydarzen.

I went to a meeting when I had arrived at university" (bo zakładam, że tak musiał powiedzieć?),

That would mean that he went to the meeting after he arrived at university. In other words, some time lapse between the two events would be duly encoded as relevant. If the time lapse separating two events is nonexistent or irrelevant, simultaneity is implied.

To represent two events as simultaneous--and that’s what the subordinating conjunction when is for—the preterite is used for events in the past domain:
I went to the meeting when I arrived at university.
He said he went to the meeting when he arrived at university.
He said he would go to the meeting when he arrived at university.
He had gone to the meeting when he arrived at university.
He would have gone to the meeting when he arrived at university.