▁week , ▁s elling ▁an ▁additional ▁ 1 1 5 , 0 0 0 ▁units . ▁ ▁On ▁December ▁ 5 , ▁ 2 0 0 6 , ▁the ▁album ▁was ▁cert ified ▁Pl atin um ▁by ▁the ▁Rec ording ▁Indust ry ▁Association ▁of ▁America ▁( RI AA ) ▁for ▁s elling ▁of ▁over ▁ 1 ▁million ▁copies ▁in ▁the ▁United ▁States . ▁As ▁of ▁September ▁ 2 0 0 7 , ▁Once ▁Again ▁has ▁sold ▁ 2 . 5 ▁million ▁copies ▁world wide . ▁ ▁Track ▁listing ▁ ▁Notes ▁▁ ▁sign ifies ▁co - produ cer ▁▁ ▁sign ifies ▁additional ▁producer ▁Sam ples ▁ ▁" Save ▁Room " ▁contains ▁samples ▁from ▁" St orm y ", ▁performed ▁by ▁G á bor ▁Sz ab ó . ▁ ▁" He aven " ▁contains ▁ex cer pts ▁from ▁" He aven ▁Only ▁Kn ows ", ▁performed ▁by ▁Mon k ▁H igg ins ▁ ▁" Each ▁Day ▁G ets ▁Better " ▁contains ▁a ▁sample ▁of ▁" In ▁These ▁Ch anging ▁Times ", ▁performed ▁by ▁The ▁Four ▁T ops ▁ ▁" S low ▁Dance " ▁contains ▁samples ▁from ▁the ▁composition ▁" She ' s ▁a ▁Fox ", ▁performed ▁by ▁the ▁I c emen ▁featuring ▁Jim i ▁Hend rix ▁ ▁" An other ▁Again " ▁contains ▁samples ▁from ▁the ▁composition ▁" L ost ▁for ▁W ords ", ▁performed ▁by ▁Mid night ▁Mo vers ▁Un limited ▁ ▁Person nel ▁Cred its ▁adapted ▁from ▁album ’ s ▁l iner ▁notes . ▁▁ ▁Chris ▁Allen ▁—   ass istant ▁engineer ▁(