No consumption horizon

Hi

Has any one designed/used a system where there is 0 forward/backward consumption horizon?

I am talking about the consumption mode and periods that are set in MRP and that get transferred to APO location-product demand tab.

In my experience I have always seen this maintained but an interviewer asked me what if they are not maintained. I am wondering if any one has not maintained these and worked out.

Thanks in advance for your time and advise.