Albany Park to Uxbridge via Stratford?

Hi all, I’m looking at travelling from Albany Park to Uxbridge during off-peak with an Oyster card with National Railcard. I believe this should be doable without going through zone 1 (change at Lewisham to DLR, change at Stratford to Mildmay, change at Finchley Road to Metropolitan) which should mean the journey is zone 2-6 NR-T costing £2.60 (including railcard discount). However, the calculator on this website suggests that the journey is only zone 1-6 NR-T and thus costs £4.65 no matter what. Is this a mistake with the calculator? Will I still be charged the higher amount even if I transit through Stratford and use the pink card reader?