Service station factors in monotonicity of retrial queues

A retrial queue consists of an orbit with infinite capacity, a service station, and a queue with finite capacity B. If any customer attempting the queue is blocked due to saturation, he then enters the orbit where the customer waits for some time, called retrial time, before the next retrial attempt. We show that if the hazard rate function of the retrial time distribution is decreasing, then stochastically longer service time or less servers will result in more customers in the system.