dece2011

Under GAAP FCFF = CFO + Int(1-t) - Capex  you don’t need to add back D&A cause it’s already done to get to CFO and no need to substract Inv in NWC cause it’s already taken care of through CFO.
Under IFRS if int exp are part of CFF no need to add them back, and to your question about reconciliation there is no flaw because adding back interest to CFO on GAAP will make the firm loose some of the tax saving so we need to capture that; remeber tax expense are part of CFO under GAAP.