the Time in the Picking Queue (TPQ) per SKU: it is the delay time that goods in the delivery process wait for an empty pallet tobe palletized after the picking process. If empty pallets are not yet available in the LSP warehouse, unloaded goods wait in a queue until empty pallets are available. The simulation model has evaluated two indicators: TPQprod and TPQLSP are times estimated at the producer and at the LSP firm respectively