Thanks for the submission.
Here's the thing: the TA score of a game is not set me any staff member of the site, it is based off a set formula. The formula for how the TA Ratio is calculated is sqrt([number of gamers who have played the game or DLC]/[number of gamers with the achievement]). The TA Ratio is then multiplied by the gamerscore of the achievement in question, and the resulting number is the TA Score.
In this case, a member of the site has unlocked the last four achievements for the
Collection 3: Chaos Pack for Call of Duty: Modern Warfare 3 DLC. Since over 2,000 people have played the DLC, but he is the only one to unlock those achievements, so the TA Ratio for them is extremely high. As more people unlock the achievements however, the ratio will begin to drop, and the numbers will settle in to more expected ranges.
Hope this helps, and happy gaming!