actually i've kinda resolved the issue.
it was the wording of the assignment was misleading.
looking in battlelog i have 196 different "styles" of dogtags... its only when you count the multiples of each style do you actually get the number of dogtags actually taken.
pehaps changing the wording of the assignment is needed since it goes on the number of different styles of dog tag taken... not actual number of dog tags in total taken.
http://bf3stats.com/stats_pc/Simmo2302/history#global.dogtags
http://battlelog.battlefield.com/bf3/soldier/Simmo2302/stats/383114857/
http://i203.photobucket.com/albums/aa304/simmo2302/screeny2.jpg
http://i203.photobucket.com/albums/aa304/simmo2302/screeny.jpg