My experience is that if you make the election to opt out of all SDA on screen 22 with the button just below "Depreciation (4562)" (the button next to the  Vehicle Expense button)   it carries forward with the proforma.  If in the subsequent you don't want to opt out, you have to go back and uncheck the box.  Using this button suppresses SDA on all classes and generates the election statement.  When opting out on just one class, the election must be made on each asset in that class using the in the next section on Screen 22 "Asset Information" under General .  IIRC this won't proforma like the blanket method.