Hi,
Cross check did you set - Dispatch time 3 for PO output type by using t.code: NACE, Application EF -> Output type -> select your PO message type and also check to set Dispatch time 3 in condition record in MN04 / MN05 t.code.
To get Multiple Print Out of same PO number,In General Data TAB select check box of Multiple issuing & save by selecting your PO message type in t.code: NACE, Application EF -> Output type.
Regards,
Biju K