SE, what does Cover do?

Hi SE,
The player base has tested Cover and described it below. They say Cover does nothing on activation or requires that player being covered to have the monster's attention. Can you clarify Cover for us?

This ability allows you to take damage for a party member who currently has hate, as long as you are standing between them and the enemy.
Cover cannot intercept AoE attacks or spells. Both the PLD and covered player will be hit.
While cover can intercept ranged attacks and spells(occasionally), the cover target must be within melee range of the monster for attacks to be intercepted.

Duration is based on dSTAT between user and target. The formula is something like:
15 + min(max(floor((user VIT + user MND - target VIT*2)/4),0),15)
Duration is determined on use. Gear can then be removed.
Duration can be further modified by PLD Job Points, up to +20 seconds.

When a hit is intercepted the PLD gains a static +200 Cumulative Enmity, and the covered player's Cumulative Enmity is reduced by 10%.
The hit must land. 0 dmg hits count. Misses don't count. Shadows/Anticipates/Parries untested.
Volatile Enmity is untested.
JA activation does not trigger this effect.