Audit Trail Type Definition

Dear ALL Experts,

I'm working on SAP BPC NW version 10.0.

When we process Audit Trail Dimension, we have to provide the Audit Trail type (i.e. "A","I" and "M").

Per my understanding, A means "Auto" which is used to capture calculated result from those Elimination and Consolidation. It is pretty clear I guess.

Just, I get no idea when we should use "I" (i.e. Input) and "M" (i.e. Manual).

Per default application, I guess "I" is used for inputting through input forms while "M" is used for putting through journals.

But still, actually you can input in input forms using Audit Trail type "M" members or putting through journals by selecting Audit Trail type "I" members.

Can someone explain the above?

Cheers!

Antony