Answer
The queue_id number itself isn't a priority indicator — rather than assuming queue 4 gets special built-in prioritization, open the 'Database Processes' screen in Enterprise Explorer, which shows one row per configured batch queue, and directly compare every configured value between queue 4 and your new queue side by side, including each queue's actual Job Action definition, to find whatever's genuinely different between them. If a queue's configuration or internal state needs to be refreshed after making a change, there's a 'Re-init Batch Queue' RMB option directly on that same Database Processes screen.