CRA claims that there is an obligation to file amended T4As for subsequently discovered errors

Reg. 200 simply requires the filing of prescribed forms, such as a T4A, for listed types of payments.  CRA infers that the Regulation creates a continuing obligation to report the correct amount, so that if an error is discovered, a corrected T4A must be issued.

Such an obligation cannot arise in the absence of clear language, and instead there is none.

Neal Armstrong.  Summary of 18 October 2013 T.I. 2013-0494441E5 under Reg. 200.