it is said on the Internet that the data dispersion of the modular algorithm is good, but this is not the case when I use windows+php+memcache testing locally. Looking at the memcache cache through the memadmin visualization tool, it is found that the number of caches on the three memcache servers is quite different, which is 15,29,55 pieces of data respectively. Why is this so?

<?php
    $memcache = new Memcache();

    $host = "127.0.0.1";

    $port1 = 11212;
    $port2 = 11213;
    $port3 = 11214;
    
    $memcache->addServer($host, $port1);
    $memcache->addServer($host, $port2);
    $memcache->addServer($host, $port3); 
    
    $key = "key";
    $value = "value";

    for ($i = 1; $i < 100; $iPP) {
        $status = $memcache->set($key . $i,  $value . $i);
    }