A question about conditional statement in loadBalancer

Hello,
I'd like to ask this small question I found while looking at the loadbalancer code below.

https://github.com/apache/openwhisk/blob/master/core/controller/src/main/scala/org/apache/openwhisk/core/loadBalancer/ShardingContainerPoolBalancer.scala#L417

According to my understanding and comment, it seems to be a conditional statement to know whether it have gone through all the invokers or not. However, stepsDone starts counting from zero, and the numInvokers initializes with invokers.size. I think the condition should be
stepsDone + 1 == numInvokers .
Could you explain what is the meaning of that condition?
Thank you!