What Mr Cook said is absolutely right. As I posted in your other question, you need to sit down and have your credit put through a credit analyzer to determine what is the culprit for any score issues you might have.
The most important influence on your credit score is your on time payment history. Whether or not paying off your mortgage will improve your score will really be determined by the remainder of your credit history (how much and how long).
Only a credit professional can give you an answer and only after reviewing your entire report.
Best regards, Kristi