Miniature Collection Set I and Set III require all shown Minis, yet Set II just requires 44/46 shown Minis for completion.
before completion: http://puu.sh/owDGS/52fccc9f9c.jpg (42/46)
after completion: http://puu.sh/owE1c/91cd04a572.jpg (44/46)
So it really unlocks the achievement with 2 missing minis.
I suppose this isnt intended..or is it..?