I have another question. If spouse prefer to file MFS and any of those wants to file his/her own income what about 8958? In this scenario both are available.

And if we leave this box unchecked : Are allocated community property ...... for in communnity prop state what happens?

When this matter? Once they want to get divorced? When they want to ......? I do not know? What was the philosophy of creating 8958? 

Most of the clients who one has high income and his/her spouse has low income they did not pick up 50/50. If they do not take 8958 should leave uncheck that box? 

A hero come in here and save me from this misunderstanding.

Proseries even has no any video for this MFS, but has a lot of videos for selling E-signiture ....