i have had the same issue with Knewton
CATs as some other posters here.
I signed up for the Knewton course
having scored 660 in the official GMAT exam based on the 50 point guarantee. The guarantee worked because my score went up to 720 in the official exam.
However, my Knewton
CAT caused me extreme stress as I was scoring 580-620 in my Knewton
CATs but a day later scoring 710 on the official GMAT practice test. I was unsure about which exam was an accurate reflection of my scoring potential. Luckily, on test day, the Knewton
CAT was not representative! However, this caused confusion for me and undue stress like many others who have posted on here.
My advice is for any Knewton
student to not get stressed with a low Knewton
CAT score as in my experience it is not remotely representative of an official GMAT score.