Perhaps my post title was unclear, but I don't think post #1 was.

My complaint is not that we cannot upgrade from Y to J if Y+ exists or that upgrades on CX from Y+ to J are the same as Y to J.

My complaint is specifically that upgrades on BA from Y+ to J, which could be done before CX introduced Y+, now appear to have more than doubled in cost, which simply makes no sense at all.