Query to sum of two kube metrics


I’m trying to get the total run time of the pod. With the below query i’m able to get the individual pod level run time and able to plot it on grafana
kube_pod_completion_time{pod=~“loyalty-auto."}) - (kube_pod_start_time{pod=~"loyalty-auto.”}
But when i try the same query with sum then it’s not returning the correct total of all the pods run time

sum((kube_pod_completion_time{pod=~“loyalty-auto."}) - (kube_pod_start_time{pod=~"loyalty-auto.”}))

Any help is greatly appreciated.