Single Processing for CCTR entity type

Hi

I want to create cost center using single processing .

Steps followed for this as below

1. Create Blank CR with CR Type OG_S003 (With Entity Type CCTR) with deselected single processing check box under  Create Change Request link. CR is created for entity type CCTR and CR Type as OG_S003.
2. Try to create cost center under Single processing by selecting Entity Type Cost Center,Proper Edition,Controlling Area and Cost Center value to be created it fives me error as no change request assigned to you.

Here my question is there is already CR for cost center then why SAP gives me error?

1. When I  try to create Blank CR with CR Type OG_W003 (With Entity Type CCTR) with selected single processing check box under Create Change Request link.it gives me error at step no 3 ' 500 SAP Internal Error'

Is I am missing something?

I can able to create CC with same CR created as mentioned in point no 1 with cost center group as entity type but not for Cost Center as entity type.

Can anybody explain SAP logic behind this?