keesje
You are very good at pretending not to understand.
What would be technically and commercially ideal today would be to assemble A319, A320 and A321 on the same line. Politics messes that up sometimes.
This is a family. A lot of contracts give the customer the right to change the 319/320/321 mix a given number of months ahead of delivery. This is relatively easy (and can be done fairly late in the leadtime) if it's just juggling slots on the line.
Now what if an A322 customer decides to take A321s instead? Where's he going to get his A321s from if that line is fully booked? Or he wants to change 10 ordered A320s to 10 A322s if that line is full? The customers would have to decide a lot earlier to make a swap.
This will be my last post here because it's getting tedious.
I promise you if you were given 20 mins to present your case to the Airbus commercial team, you'd be invited to leave after 10. Your propostions are based too much on what is possible and not enough on why it should be done. No I don't work for Airbus.