Correct , lets say you want member number 666 to have 1500 posts.

SQL Query
UPDATE `ubbt_USER_PROFILE` SET `USER_TOTAL_POSTS` = '1500' WHERE `ubbt_USER_PROFILE`.`USER_ID` = '666';

I have used this in the past where say I pruned a lot of posts and then ran the re-builders.
This will cause the members of the posts to loose some on their post count.
So usually the most active members complain.
Like "Hey I used to have 4500 posts now it shows 2500 posts".
So I appease them by modifying their post count back to what it was.
Of course it would be crazy to do say 6000 members one at a time.
Let alone know what there were supposed to be.