That's a difficult question to answer because I don't know whether the original cost was, in fact, a solid estimate at that time. Assuming it was a very solid cost estimate, making the decision early and starting early with the development and acquisition of these ships would certainly have been a good way to avoid incurring these ever-increasing additional costs due to delays.
As I said before, the delays might have been totally justified. They may have been justified by design changes necessary to meet the Royal Canadian Navy's needs, or they could be things deemed to be desirable, as opposed to indispensable. For these reasons, the reasons behind the delays are probably better explained by National Defence.