So currently in my game:

1) I have the 4 holotapes associated with the Replicated Man quest. I don't remember where I got them, but I got them.

2) Quest log mentions finding out (optional) what Dr Preston knows about the Android, but when I talk to Doctor Preston, I do have an option to ask about the android, and yet there seems to be no updating of the quest log involved.

None of my logs for this particular quest seem to be updating as far as getting new information from the people, even though they all have information (other than Sister that is, he doesn't have much in the way of speech options).

So I was curious if there was something I missed in the game, which is why it's not updating about "find more information" about the android, nor is it updating when talking to Dr Preston.

If I didn't miss anything, then can I possibly get some text codes (since this is PC I am playing from) so that I can manually update the quest log itself to show I've completed the optional part of the quest? I dunno if I get any extra rewards from it or not.

I don't know if it's the same for PC as it is for 360. but I only get credit for Preston if I find more holotapes. It never updates, even when passing a speech check or even paying the 100 caps.
Spoiler, where I found holotapes:

Yeah, I read through the fallout.wikia.org page that there is a known issue with that quest involving quests not updating. So really there is nothing I can do about it. :/