Unexpected calculation

I have some unexpected results returned within my application; here is an example:

```
$schedule = SLASchedule::create()->from('08:00:00')->to('17:00:00')->onWeekdays();
$sla = SLA::fromSchedule($schedule);
$result = $sla->duration($start, $end)->totalMinutes;
```

start: 27/04/2023  15:43:00
end: 28/04/2023  13:02:00

Should return 379
instead, it returns 76
