I have my 200+ trades converted at the daily CRA exchange rate. When I change the T5008 data submitted by TD/ToS to include both book value and disposition amounts which are NET( TD submits only GROSS disposition values in USD) and converted into CAD the day rate, CRA will not be able to reconcile against TD/ToS submission. If CRA were to inquire, I have a detailed 15 page excel spreadsheet report to back my submission up.
CRA will accept this change in reporting of your T5008 information. As long as you have that spreadsheet to back up your claims, you should see no problems.