Mr Seatback 2.. You are correct indeed.
If a qantas employee transfers from a ground based position into a flying position, years of service, start date, etc remain and a "flying seniority start date" is created along with a "seniority number" If this staff member starts with external applicants for example, regardles of age, this person would be considered "senior" to their fellow Groundschoolers in regards to seniority as they were already within the company. This does not apply for a subsidiary employee applying via blue notice as they are forced to resign and given new start date etc.
Divisional Transfers, ie: Regional/Short/Long. Nothing changes..years of service, seniority, sick leave, holidays etc, remains.
Again hope this all helps. Good luck all.