[douglas]

The other 4% comes from racial and/or cultural bonuses. "Average" covers the whole range from 100% to 104%, plenty of room for a mere 4% difference to show up without changing the description to the next category. The difference could be as high as 8% without either race being non-"Average", or even higher if one of them has a higher cultural space combat bonus than the other.

Edit: It's "High-Energy Discharge Weapons" for the Wave Motion Gun. Incinerator Beams from the same tech area also have an accuracy bonus. Neither weapon's damage output is high enough to be worth it in most situations imo.

The High-Energy Magnifier also has a +30 to hit combined with better damage output than the WMG, but it's a crystalline racial tech weapon.