If they’re not in use, they show 0.0 but, to use them, you have to use their hotkey several times just to get to 1.0 and -then- you can get bonuses. Click the key once by accident and you’re suddenly doing 0.1 damage.
Wouldn’t it be better if they defaulted to 1.0 and, from there, people could choose to do more or less damage?
(Same goes with any similar slider like an XP Modifier)