[SOLVED]Collar broken in game...(´;ω;`)

Hello.

I am making a sailor dress and it looks fine in sims4studio.


But in game, the collar will broken like this:



When sims move, it becomes more horriable.( ´•̥̥̥ω•̥̥̥` )




I tried to edit the weight paint (UpperArm, ShoulderTwist). It looks better:


But when sims move, it still has the same problem on the collar:


Besides of this, when I change the shoulder breadth, the collar also broken. 

Only the widest shoulder breadth is ok.


How can I fix this? Thank You.(´;ω;`)

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Blender: v.2.76 + 2.70(for weight transferring)
Sim4studio: 3.0.1.4 (Harmony)
Package & .blender: [DEL]
P.S. Sorry for my poor english. (つд⊂)