Some clarification:
The damage number you see is actually the average of your weapons.
Since every click/attack actually does 2 hits, you can double that to predict your damage per click.
Also don't forget that you don't do base damage with both weapons. Your dual wield weapon expertise decides the damage modifiers on each weapon before the average is taken. Lvl1(untrained) for instance your main hand weapon does 101% damage but your offhand weapon only does 30% of that weapon's base damage.
BTW this is not a new rule. No rebalancing was done on this logic.
