Exchange difference on Goodwill

Hi Sir Chris! I was just wondering why the calculation for exchange difference is different between Sept/Dec 2015 and June 2011 examination as shown below... When I use the June 2011 style to Sept/dec 2015, i get a different answer for exchange difference. I tried to fix the format but it just would not show when posted... Hope to hear from you soon. Thanks. Sept/ Dec 2015 (Loss on Exchange Difference) Goodwill Dinars Ex-rates $ Consideration 368 FV NCI 220 NA at Aquisition (468) ______ 120 DOA 8 15 Impairment (120)(20%)= (24) Avg 8.5 2.8 ______ 96 DOC 9.5 10.1 Exchange difference (12.2-10.1)= 2.1 Impairment Loss = 2.8 June 2011 Goodwill Dinars Ex-rates $ Consideration 276 FV NCI 250 NA at aquisition (495) _______ 31 Exchange difference on Goodwill Consideration 276 NA at aquisition (495)(52%)= 257.4 _______ 18.6 18.6 @DOA rate 6 = 3.1 18.6 @DOC rate 5 = 3.72 ______ Exchange difference gain= .62