A few thoughts...
1) If you've used a lot of Kaplan
materials, you'll definitely get used to their writing style, which is different from the style of the actual exam. Inevitably, you'll learn to see Kaplan
's traps, and you'll do much better on their tests than on the real thing. The same would be true of MGMAT--if you've used their materials heavily, you might do disproportionately well on their tests.
2) Maybe you saw some repeat questions when you scored a 600 on the Kaplan
3) Non-official tests (anything besides the GMATPrep) are inherently unreliable, at least to some extent. These tests are the work of some very smart people who are trying their best to reverse-engineer the actual GMAT test... but they aren't the actual GMAT. They differ from the actual exam in all sorts of subtle ways, and it simply isn't unusual to see huge discrepancies between Kaplan
(or MGMAT or Veritas
or PR) tests and the real thing. Sure, your gap is larger than most, but it isn't unheard of.
4) As you mentioned, maybe you were having a bad day?
5) Have you taken the GMATPrep tests
before? If so, is the 490 close to your previous GMATPrep score(s)? If your GMATPrep and actual GMAT scores are in a similar range, then it suggests that the Kaplan
test might be giving you the wrong impression, unfortunately.
I hope this helps!
Helping students kick the GMAT in the nuts since 2002... www.gmatninja.com.