not necessarily, i also got the impression they were implying zeus since hermes was refering to him as old man, which is a common way someone may refer to their father. also, if you read the trial logs, you can see that zeus wasn't particulary eager to vote one way or the other but, with the pressure of bringing the trial to an end, he likely rushed his vote. there's the possibility that he came to regret his vote later and, extrapolating a bit, the results of the trial might have led to the downfall of the olympians. naturally this is all conjecture with no confirmation whatsoever, but it could work with the narrative available to us. the one thing that doesn't fit is that the letter was signed P.