Rounding Down Values / Rounding Profile in Delivery

Hi

I have a query regarding Rounding down Value / Rounding Profile

Our system currently rounds to full case pack if the customer orders in partial quantity.

Please advise if it is possible to only round DOWN to full case Pack.

This is a customer specific requirement not applicable to all. customer does not want to round up.

Plse help me with configuration.

Thanks

Rajesh