Does +damage round up or down?

Let's say I customize a weapon for its +20% damage.

If it's initially 13-19, the modifier makes it 15.6-22.8.

Now, does this round to 15-22 or 16-23?

Also, does -damage round the same direction?

Or does it round down below .5 and up above .5?

I read that the AL rounds to the nearest whole number. I would assume damages are calculated the same.

AFAIK, in this game, whenever rounding occurs, it's always towards the nearest whole number. However:

I believe the answer to this question is neither. In fact, under these circumstances, your weapon damage actually is 15.6-22.8. If any rounding does occur (and I'm not sure if it does other than for display purposes), it wouldn't occur until after other factors in the actual swing are calculated (the target's armor, any damage boosting spells, armor penetration, etc). If you started with either the 15-22 or 16-23 figure in trying to calculate what the actual damage range will be, you'd get the wrong answers. The correct answer in this case is that the weapon's damage before those factors are taken into account is 15.6-22.8.

I've never been a invinci monk, but they tell me that with 55 hp they only take 5 damage per hit. In this case 55 * .1 (protective spirit) = 5.5, so one would think that the enemies damage would round to 6. Anyone know why it's instead rounded down, and would this downward rounding also exist if it was X.9? Thanks for any feedback. I'm quite curious as to how rounding really works. Also, I'd like to know how skill duration is rounded, when in conjunction with blessed aura (or any other skill duration modifiers -- like weapon mods).

Don't quote me on this, but I think GW tends to truncate numbers rather than rounding. That is, anything past the decimal point is just ignored.

well, all i know is, having 12 expertese definatly round to 50% reduction of energy cost.

Which is, in effect, rounding down. Still, a rose is a rose is a rose.

Where are Epinephrine & Ensign when you need them?

Read this off GWonline, the reason why you only receive 5 damage with protective spirit covering your 55 life is that, protective spirit can't allow any damage to go higher than 10% of your life.

Thus, the damage isn't rounded up due to protective spirit. Hope that helps you.