If you are filing late (or doing T1 adjustments) for clients that involve pension income splitting it is advisable to verify whether or not it is advantageous to do pension income splitting at all. In certain cases the penalty and/or interest charges that result from the late filing (or T1 adjustments) might come close to or even nullify any net tax savings coming out of pension income splitting. This might prove to be more of an issue in situations where the net tax savings resulting from pension income splitting are small. Compare the results with and without pension income splitting and see which nets out better for your clients once all factors such as penalty and interest are considered.