How can you tell that it does not?
The multiplier bonus only applies when you're wielding a 2H weapon. If you spend points in Two-Handed, then check the tooltip of any 2H weapon, you'll see that the crit multiplier changes accordingly, i.e. 195% Critical Damage will become 205% Critical Damage if you have 2 points in Two-Handed.
Now be happy, cause I just did the hard part for you. I just tested it in game, and the bonus multiplier did apply correctly.
Two-Handed rank 0: 1224 normal damage vs. 2375 crit damage. That is a 195% multiplier.
Two-Handed rank 2: 1248 normal damage vs. 2587 crit damage. That is a 205% multiplier.
