CK is the worst. It had my credit score frozen for nine months before I cancelled, yes cancelled the service. It had me listed at 687 for that entire time. I had a FICO inquiry pulled toward the end of that 9 months through a mortgage lender and my middle score was 729, low 723 and high 739. When I attempted to contact them about the discrepancy they ignored my emails. After about five emails over a one-month period, I finally gave up and cancelled. My guess, based on the standard discrepancy from Credit Sesame (about 40 points low), is that my current middle FICO is likely now over 740. My last FICO pull from myFICO was 735 about two months ago with perfect everything behind it.
Also, if you had a student loan with Direct Loans during the servicing transition period, CK treats it like a new account which kills your credit score. That kicked me from 698 down to the stagnant 687 from which it never changed back. They simply suck at what they are doing.