Possible error in sleep logic

There may be a logic error in the expectations for the duration of sleep within the process_login_fail function.

As commented by convissor within ​ticket #1548 the line $sleep = 0 is "needed" from the below code taken from 0.14.0.

But in each though the if, else and elseif the value always gets replaced with a random value between 1 and 60.
Is this expected?

		$sleep = 0;
		if ($fails['total'] < $this->options['login_fail_tier_2']) {
			// Use random, overlapping sleep times to complicate profiling.
			$sleep = rand(1, 7);
		} elseif ($fails['total'] < $this->options['login_fail_tier_3']) {
			$sleep = rand(4, 30);
		} else {
			$sleep = rand(25, 60);
		}

Is there a case where $sleep is expected to be zero?

As further down it is tested for:

		if ($sleep) {