I think the issue should be head type or the card itself.
I also got the same result as yours.
At first I thought its the head type fault since you arent quite supposed to use next gen skin shader on toon styled character and bcs of that, Hanmen made a toon shader. But the issue still persist even after I changed the shader to default and toon shader.
But usually when you're getting this kind of card, they're usually in a set of chara and coordinate. But from what Im getting this card, it only gives you the chara. So maybe the original card have a coordinate that hide the skin difference at the neck.
I found that you can change the value of AlbedoOpacity in head's ME window to something between 0.94 to 0.95 to minimize the difference.
I think you wouldnt notice the difference unless you zoom in really close or changed the Glossy or Wetness slider.