Clarification regarding Istio Load Balancing

I had a doubt. When we specify the load balancing technique that we want to use using destination rules (for a particular k8s service) , is the load balancing done amongst all the pods of that service or within a subset (version) of that service (means each subset is considered independently when load balancing is concerned).
A sample destination rule for reviews service of bookinfo application

I had this doubt because we can control the amount of requests that are routed to different versions of a service using Virtual Services.