try the 310 area did not seem to want to die then try killing just one still did not see to want to die so todo it solo seem like maybe need more information on how to get them kill

the "AP recommended" missleading AF, instead they should stop faking it and put "combined AP" + accuracy to show as recommended.

On the patch note, devs gave more informations. I didn't try it myself yet, so it may not be properly working? 

City of the Dead

Monsters in the City of the Dead can be knocked down by successfully administering a simple gimmick. 

When the Tehmelun Messenger, leading the monsters, performs a certain action, using a CC skill (regardless of type) will cause all nearby monsters to fall down. 

Then, you will have the Essence of Ulukita buff applied to easily defeat the monsters. 

The key is to take advantage of this situation and sweep the monsters away.

Tungrad Ruins

The combat method in the Tungrad Ruins is similar to that of the City of the Dead.

Among the groups of monsters, there are Tungrad Visionary monsters mixed in.

If you attack these guides first and detonate them, you can receive the Essence of Ulukita effect, and all the surrounding monsters will be stunned and have their DP decreased.

The key is to quickly defeat them in this situation.

As far as I know , they gave the information for the correct AP ranges for these spots already, with the combined AP.
And yes, if the mechanic is not done correctly, the mobs are extremely tanky. But once they are KDed, you deal a ton more damage with the buff on you, and can burst them down very quickly.

You have to CC the "leader mob" (whatever its name is) during an animation it does.  When you do, the rest of the mobs get KD'd and are easily bursted.  If you miss the CC on the leader mob, it will do a powerful attack, so be careful as it can 100-0 you very quickly (RIP Magic Crystal of Crimson Flame - Power).  Other than that, it's a pretty chill grind, good mob density, lots of rotations, just too bad it's pretty much DoA content.