Library doesn't work, false result

[vipera7]

Hello,

I'm attempting to utilize the library for calculating durations between two dates. Here's an example:

<?php
require 'vendor/autoload.php';

use Sifex\SlaTimer\SLA;
use Sifex\SlaTimer\SLABreach;
use Sifex\SlaTimer\SLASchedule;

/**
 * Create a new SLA between 9am and 5:00pm weekdays
 */
$sla = SLA::fromSchedule(
    SLASchedule::create()->from('09:00:00')->to('17:00:00')->onWeekdays()
);

$dateTime_start = DateTime::createFromFormat('H:i:s d-m-Y', '16:58:00 01-12-2023');
$dateTime_start->setTimezone(new DateTimeZone('UTC'));
$utcFormat_start = $dateTime_start->format('H:i:s d-m-Y');

$dateTime_end = DateTime::createFromFormat('H:i:s d-m-Y', '09:01:01 04-12-2023');
$dateTime_end->setTimezone(new DateTimeZone('UTC'));
$utcFormat_end = $dateTime_end->format('H:i:s d-m-Y');

$duration = $sla->duration($utcFormat_start, $utcFormat_end);

var_dump($duration->totalSeconds);
var_dump($duration->forHumans());

Output :

int(120)
string(9) "2 minutes"

The expected result is 3 minutes 1 second. Can you help me understand why it's calculating this way?