I've read that for Skyrim, timescale below 6 ruins quests and other stuff. I've got mine set to 4 because it's an even number ( wrye bash ) and suits me fine, but I've hardly done any of the main quest ( in fact the amulet of kings is still in my inventory ). I read the descriptions of all mods I install and none of them ever said anything about timescale, including FCOM. I think Integration Integrated may have mentioned something, but I'm not running Integrated, not yet anyway. Since Oblivion is the engine before Skyrim, does low timescale ruin things in Oblivion such as quests?

I vaguely recall some vanilla (?????) quest that supposedly doesn't work as intended with an adjusted time-scale. That said, my time-scale was set to "10" within seconds of my avatar waking in an imperial prison cell. It's caused no issue that I've noticed. Admittedly he never involved himself with the assassin and thief guild quest-lines. Then again this might be something fixed via the Unofficial Patch.

-Decrepit-

There have been reports from some players that a small number of quests, (such as "Paranoia") do not function correctly with very low timescales. Myself, I have never experienced a problem. I have always set my timescale between 12 and 20 and I've never experienced a problem with any of my quests, including "Paranoia."