I guess they will back into it saying if you were an existing user you might have jam points, which can be applied toward the cash cost. But then again if you have gear credits, I don't think you can apply jam points to get a reduction of gear credits for the upgrade. In that case you can buy more gear credits discounted by the jam points. I believe that is the current model. (apologies if wrong.)
They could/arguably should do something like give existing AT3 users 30 gear credits that could be used toward the upgrade. That would seem to fit into the system they set up.