When is 'Clearing Balance Sheet' and 'Clearing Inc Stmt item' used?

Hi,

In what circumstances, clearing balance sheet item and clearing inc stmt items are used. Commonly, it's used for balance carry forward task, where system recognized the net profit for the year (in PL) and current ytd profit (in BS).

i was trying to post the following entry via manual posting and system generated additional 2 lines:

DR Sales 100

CR AR 100

DR Clearing BS item 100 < System auto generated additional one line

CR Clearing PL item 100 < System auto generated additional one line

(The above entry is enter at posting level 01)

I was trying to post another 2 balance sheet items via manual posting at posting level 30. There was no additional 2 lines created.

Please advise.

Regards, Renee