если верить
http://www.wowwiki.com/Weapon_damage
Non-normalized attack-power-modified weapon damage
The damage displayed in the Character Info window's Damage tooltip is modified by attack power. This damage range is used for white damage, and is generally used for non-instant attacks. It is also used for some weapon damage based instant attacks, see normalization for details.
то в окне перса показует дмг только для автоатак, а для фс нужен именно нормализированный дмг, формула которого написана ранее