Evaluation Order of Multiple VS targeting The Same Workload

Networking
1

Hi hows it going everyone. Im having trouble understanding how multiple virtual service entries targeting a host are evaluated. We have a legacy api endpoint that is an aggregate of several services. When I route traffic to books.qa.svc.cluster.local from the my-api vs, the canary rules from the books-service vs are never applied. I think I have a fundamental misunderstanding of how these rules are meant to work.

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: my-api
  namespace: qa
spec:
  gateways:
    - public-gateway.qa.svc.cluster.local
    - mesh
  hosts:
    - api.something.com
  http:
    - match:
        - uri:
            prefix: /books/
      route:
        - destination:
            host: books.qa.svc.cluster.local
    - match:
        - uri:
            prefix: /authors/
      route:
        - destination:
            host: authors.qa.svc.cluster.local
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: books-service
  namespace: qa
spec:
  gateways:
    - public-gateway.qa.svc.cluster.local
    - mesh
  hosts:
    - books.qa.svc.cluster.local
  http:
    - route:
        - destination:
            host: books-primary.qa.svc.cluster.local
          weight: 50
        - destination:
            host: books-canary.qa.svc.cluster.local
          weight: 50
---