So Nissan sells those lines that run under the bottom of the car as a single unit.
I bought them, but then the mechanic tells me that they can be separated and the AC lines replaced w/o opening up the heater lines and draining coolant.
They just replaced my AC lines which had a nick from running over a curb years ago. So I have brand spanking new heater lines sitting around just in case.
What a rip off by Nissan.

Nissan is not the only OEM that does that, it is common now to have individual parts preassembled into unitized subassemblies that cost much more, it forces you to buy parts you don't need to get the ones you do. What they have to do to support all those glass fancy dealerships. It's to bump up individual parts sales for more profit.

Ford began to do that 20 years ago, You practically cannot get any single part from them any longer, only whatever subassembly they can roll up the smaller parts into now. I was told by parts guys back many years ago that Ford was looking to make the average parts sale $75 or more, the dealer could not survive anything less. That was around 9/11/1 time.