I think the fundamental difference is that Plushenko and Shen/Zhao were not the reigning World Champions, nor had they even competed at Worlds in that quadrennial leading to their comebacks in 2010, let alone competed a whole lot.
I get that rankings are rankings, but it's pretty silly to have the reigning World champion not even skate in the final 2 groups, let alone final group. Particularly on a stage like this. Get ready for the onslaught of PCS bs.
But Plushenko (2006-2010) and Shen/Zhao skated at grand prix, grand prix final or europeans in Olympic year, unlike Kim. And they are former world champions. I'm very sure Kim will be safe for PCS.