Setting Ingress and Egress Relicas using IstioOperator values overrides

Contributors Operator
1

I am trying to use values overrides for the gateway replicas using this

apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
spec:
  profile: default
  components:
    egressGateways:
      - name: istio-egressgateway
        enabled: true

  values:
    gateways:
      istio-egressgateway:
        env:
          # Needed to route traffic via egress gateway if desired.
          ISTIO_META_REQUESTED_NETWORK_VIEW: "external"
        autoscaleEnabled: false
        replicaCount: 3
      istio-ingressgateway:
        autoscaleEnabled: false
        replicaCount: 3

and this fails for

istio-1.10.3 % istioctl install -f bugtest.yaml
Error: validation errors (use --force to override): 
unknown field "replicaCount" in v1alpha1.EgressGatewayConfig

I modified the egress gateway replicas to be part of the spec

apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
spec:
  profile: default
  components:
    egressGateways:
      - name: istio-egressgateway
        enabled: true
        k8s:
          replicaCount: 3

  values:
    gateways:
      istio-egressgateway:
        env:
          # Needed to route traffic via egress gateway if desired.
          ISTIO_META_REQUESTED_NETWORK_VIEW: "external"
        autoscaleEnabled: false
      istio-ingressgateway:
        autoscaleEnabled: false
        replicaCount: 3

And that worked fine.
I am wondering if there are some restrictions regarding istio configuration parameters in the values section and if so, what would they be?

Thanks
Doug