ldap_search results limited

I am running into a problem with my queries returning a limited number of result entries. The LDAP server is Kerio Mail Server, and I am verified that the SIZELIMIT in the server's configuration is 0 (no limit). For some reason, my server seems to be limited to 200 results if no limit is specified in ldap_search(), or 201 (?!) if I specify a limit larger than 200.

// setting the protocol version
ldap_set_option($conn, LDAP_OPT_PROTOCOL_VERSION, 3); // returns TRUE

// getting & settings SIZELIMIT options
ldap_get_option($conn, LDAP_OPT_SIZELIMIT, $optVal); // returns 0
ldap_set_option($conn, LDAP_OPT_SIZELIMIT, 1000); // returns TRUE

// some example queries
$res = ldap_search($conn, "", "cn=*", $attrs, false, 0); // 200 results
$res = ldap_search($conn, "", "cn=*", $attrs, false, 1000); // 201 results
$res = ldap_search($conn, "", "cn=*", $attrs, false, 199); // 199 results

I am using MAMP with PHP 5.2.5. Any ideas?

- MB