The Office I am talking about did both, that is why the Saint-Laurent's were done in four batches (7-7-4 and 2), with major retrofits to the original seven into DDH's, and four of the Restigouche's into IRE's (St, Croix, Columbia and Chaudiere were left out). But they also had plans for the next frigates to start replacing the Saint-Laurent's, incorporating a lot of what the Americans were doing with their Knox class, but these were canned in the lead up to Unification, and ultimately, it was the next follow up class, destroyers, that were built instead - the Iroquois'.
Then, after unification, the bureau was dismantled, all functions centralized in Ottawa - without the industry experts, and we got silence for 15 years.