12wheeler,
I think you are giving people the impression you are booking PRI4 FOC, what you are purchasing are ID50 confirmed tickets.
If you look at the best one way internet fares for each sector, they are very close the ID50 one way. The return ticket is always a lot cheaper.
The ID50 ticket you are quoting is fully refundable and changeable, the internet fare is not. The cheap internet fares typically have a 20% of the fare price no show or change fee.