Can someone tell me an alternate solution to this Common Table Expression..

with abc as
        (
        select sum(taItemSalesPriceSet.coNormalPrice * taLinkDunCode_Item.coQty) as totallinesum
        from taDuncode
        LEFT OUTER JOIN taLinkDunCode_Item ON taDuncode.copkDunCodeNo=taLinkDunCode_Item.copfkDunCodeNo
        LEFT OUTER JOIN taItemSalesPriceSet ON taLinkDunCode_Item.copfkItemNo = taItemSalesPriceSet.copfkItemNo
        where copkduncodeno='1'),
        aaa as
        (
        select case when abc.totallinesum <> 0 then (taDuncode.coDiscAmt* 100)/abc.totallinesum else 0 end as discperc
        from taDuncode, abc where copkduncodeno='1'
        ),
        xyz as(
        select (((((taItemSalesPriceSet.coNormalPrice * taLinkDunCode_Item.coQty)  - ((taItemSalesPriceSet.coNormalPrice * taLinkDunCode_Item.coQty)*aaa.discperc/100)) - case when covatefftax <> 0 then (((taItemSalesPriceSet.coNormalPrice * taLinkDunCode_Item.coQty)  - ((taItemSalesPriceSet.coNormalPrice * taLinkDunCode_Item.coQty)*aaa.discperc/100))/((100 / covatefftax) + 1)) else 0 end)-(talinkitem_supplier.coNetPurchasePrice *taLinkDunCode_Item.coQty))) as one,
        (((taItemSalesPriceSet.coNormalPrice * taLinkDunCode_Item.coQty)  - ((taItemSalesPriceSet.coNormalPrice * taLinkDunCode_Item.coQty)*aaa.discperc/100)) - ((case when covatefftax <> 0 then ((taItemSalesPriceSet.coNormalPrice * taLinkDunCode_Item.coQty)  - ((taItemSalesPriceSet.coNormalPrice * taLinkDunCode_Item.coQty)*aaa.discperc/100))/((100 / covatefftax) + 1) else 0 end))) as two
        from taDuncode
        LEFT OUTER JOIN taLinkDunCode_Item ON taDuncode.copkDunCodeNo=taLinkDunCode_Item.copfkDunCodeNo
        LEFT OUTER JOIN taItemSalesPriceSet ON taLinkDunCode_Item.copfkItemNo = taItemSalesPriceSet.copfkItemNo
            inner JOIN TaItems ON taLinkDunCode_Item.copfkItemNo = TaItems.copkItemNo
        inner JOIN taVatCode ON TaItems.cofkVatCode = taVatCode.copkvatcode
            inner JOIN talinkitem_supplier ON taLinkDunCode_Item.copfkItemNo = talinkitem_supplier.copfkItemNo
        inner join talinkitem_profile on talinkitem_supplier.copfkItemNo = talinkitem_profile.copfkItemNo and talinkitem_supplier.copfkSupProfileNo=1
            and talinkitem_supplier.copfkSupProfileNo = talinkitem_profile.copfkProfileNo
            and talinkitem_supplier.copfkSupplierNo=taLinkItem_Profile.cofkActiveSupplierNo
            , abc, aaa
            where copkduncodeno='1' )
        (select case when sum(two)<>0 then convert(decimal(20,2),(sum(one)/sum(two))*100) else 0 end as gpp from xyz)