I am assuming that the correct carryover for the amended 2017 should reflectwhat would have occurred if the prior-years had been properly filed.
That is correct ... you had to recompute the loss carryovers for all the missed years to have the correct amount for the 2017 return ... in fact you probably should mail in the old amended returns (even thou any refunds are mute) to support the calculation of the loss carryover to 2017.
your link does not address using capital losses from a "closed" year. Not sure what you mean ... use the amendment process to add the loss in the investment section.
