Legal Question in Civil Litigation in Massachusetts

I wouldn't say it is "typical" for a credit card judgment to be less that the amount owed, although I'm sure it happens from time to time. Regarding your second question, it is typical for the court to charge interest. The amount of interest actually charged is dependent upon a few factors, however.

It is possible that the judgment was in the amount of the "charge off" balance, but that they were attempting to collect from you further interest and maybe attorney fees. The interest charged by a court is generally 12% on judgments. In some instances, a party will also be entitled to contract interest from the date of demand.

You should get the judgment removed and negotiate a settlement with the creditor!