Adam,
If you TRANSFER from Qlink to mainline or Jetstar then yes you are correct, no resetting of 6 months required. This sort of opportunity typically is available to cabin crew, ground crew?, or management staff.
There is a system available for pilots to transfer from qlink to mainline but the numbers that have used that system are so low that it's hardly even worth mentioning....you could count them on one hand.
Most pilots going into mainline from the link are going through the direct entry scheme....which requires them to RESIGN from qlink then take up a position with mainline. This means that all benefits such as staff travel, seniority number based on start date etc are reset.
It's a dumb way to do it I know, but that's the way it is.