@ Mariyasubtain,
In addition to the DD making and cancelling chgs there would be other cost as well, that you have to bear. Assuming the rate of exchange remains the same, the Bank while canceling i,t will be doing it at its buying rate which can be 05-20 fils less per Canadian dollar (as in the present case) than its selling rate, depending on the Bank's policies. In the sceneario the Dollar slumps as has happened now ??? :-X the loss in cancelling will be substantial (as per the amount) like if the selling rate of the Bank was 3.85 AED/CAD$ and the buying rate becomes 3.45 AED/CAD$ while cancelling it then the loss on this aspect alone, would be AED 4000/- :'( per CAD$ 10,000/- or AED 8000/- :'( :'( per CAD$ 20,000/- plus AED 100-150, as er2d2g has written.
In response to your query abt loosing min amt of money in this traxn the best solution would be to make the DD in US$ as it is accepted as POF for Canadian immigration purpose and secondly because the rates are static against the AED. 8) The max loss would be
(besides the AED 150/- DD making and cancelling chgs), AED 115/- per CAD 10,000/- with Union National Bank, for example or AED 320/- per CAD 10,000/- in ENBD's case. Choose a bank which has the least difference in its buying and selling rates for US$.
You can PM me for further guidance, in case you need.
Best Wishes,
Bestpal