Thanks all. Yes, the quotes I received was to paint the entire tailgate and roof panels - no blending mid-panel. And yes, the tailgate would be completely disassembled.
I did ask how much they would charge for a complete repaint - they guessed around $7,500. I have seen examples of this paint failing in other areas - most notably the A-pillars and hood.
Interestingly, it looks like Acura has a recall out for a similar paint failing on the roof and tailgate (
link).
So it seems that Kia are internally aware of the failure with this paint color, but have stopped short of an official recall.