Ben Bova hypothesized that Homer was actually describing early siege towers, but given the veracity of many mundane parts of the story it seems unlikely.
That is so, but my understanding was that those later stories tie back to a lost epic (Iliupersis) that, while not officially attributed to Homer, was being sung contemporaneously with the other stories of the Trojan war cycle.
Most of what we know of it appeared in non-Homeric stories and most famously (nowadays) in Virgil.