Forecast Consumption Planning - Customer Master A code

Hi,

What is the significance of setting up A in customer master for forecast consumption by customer? If A is not set, what are the implications?

Below is the details from oracle document:

Set the customer up as a Large Customer. Set the ABC Code for Sales to "A" in the Address Book Revisions (G01/P01012). Take the Row Exit to A/R, and drill into the Credit tab. Enter an "A" to signify large customer

Regards,

Gayathiri