Do you know why the amount of EAC was not came to be the amount of Actual Cost + Remaining Plan?

Summary:

Do you know why the amount of EAC was not came to be the amount of Actual Cost + Remaining Plan? 

I used the following Financial Plan Type. It is set Remaining Plan as Forecast ETC Method.

I tried to velidate but it's behaveor is strange.

1)The amount of Actual Cost of August is more than the amount of ETC that was set at the beggining of Project.

2)The amount of EAC should be 65,000 because there is differences between Actual Cost and ETC Plan about August.

Question1：

Why is it not 65,000 but 60,000?

3)If I open Edit Period Amounts, Actual Cost and EAC was doubled.