Advance Ship Notice ( ASN ), Uniform Code Council-128 ( UCC-128 ) carton labels, and distribution center ( DC ) mix decisions decide whether your loads glide through—or get hit with negative acknowledgments ( NAKs ) and compliance chargebacks. Why it spikes in Q4.  More promotions. More split purchase orders ( POs ). More DC reassignments. More ways your plan breaks. Fictional example (for illustration):  A home goods supplier shipped on time, but their ASN posted after gate-