There's an information about ECO's and the affected items. 

“When manually revised parts/specifications are added as affected items to an ECO, the previous released revision is added automatically to the ECO with Requested Change = For Revise. The current revision is added with Requested Change = For Release.”

I want to learn what's the purpose of adding the previous released revision to the same ECO? I mean I already attached the new modified part. Why to put the previous version again. Doesn't it create confusion on users? 

Is this an optional choice? I mean can ı configure the system that only the "For Release" parts will be attached to ECO's? How?