win 7 x64
The bonus is only applicable if the wearer speaks the command word. Otherwise it is just a cloak. Hence bonus is not permanent and no misc modifier.
I would propose that the bonus should be displayed as a conditional modifier if wings of flying are equipped.
the thing is, u only can skill in fly if u have the ability to acutal fly. that means, if u dont wear the wings u cannot even use the skill fly. (maybe only in the rare occurance of magical flight)
Wings of Flying offer a Temporary Bonus when activated. After equipping them, look under Temporary Bonuses for Items. Click on wings of flying and the bonus will be added.