Sometimes when my Sim sleeps or when he is at work, times go much faster on Ultra speed, and sometimes it doesnt. Does that depend on something or what? Hope u udnerstand me :)
I just had the exact issue and I think if your Sim has a low need (mine was bladder), then time runs slowly. I have two Sims, both of which were about to wet themselves, so after they went to the bathroom, the time sped up again.