The Devs decided this when they implemented it... Then they said when device activation was pushed for, that it is the way they intended and were not gonna change it.
Yes lets make it so a group can take the hardest raids in the game... Currently you only need two decently geared groups and the right tactics to take just about any raid in the game.
Problem with that is people will use it just to get non manu items to 125%, I know I would if I could. Just a little exploitable. Unless the quality increase goes back down after the allotted time.