User blog comment:Mr Bio Shock/Attempting to Understand Infinite's Ending... (Spoilers, of course)/@comment-3048593-20130329212731/@comment-69.85.234.252-20130405150034

Oh, sorry. "Comstock" was the name closest to the subject of that sentence, so I assumed. But I was wrong to.

Well, Comstock is aged and changed by the experiments, not to mention his much changed personality due to the baptism (and possible insanity, once again from the experiments). Plus he grew a beard, so y'know. Not to mention he only heard the voice through distorted voxophones the first good portion of the game, then heard it distorted differently in person--then only saw him from a distance for a while, before the end.

Plus there's the nosebleed stuff (present all the way back to the first confrontation with Comstock: "This will end in blood"). It's possible DeWitt's memories and thought processes  were compromised by time stuff.