Average item levels seem to be wrong

[WintersMoondancer]

Is it just me, or is the average item level a bit off when you have to total all your equipped gear and divide by 12 to get the average. Yet some jobs do not have offhand equip-able items and when wearing cowls you actually lose on item level average. Is this "working as intended" or is this flawed? Makes a difference when joining groups in Party Finder and you don't meet the average level required because you have a cowl on and using a two-handed staff.