You're not comparing apples to apples...you're comparing a composite Kaplan score to individual section scores from your PR test. PR calculates the final score for you...open up the software again and you should see that number.
Don't freak about a 530 on Kaplan. They were well-known for having tests much harder than the real GMAT and for the scores being very low. Your PR score and GMATPrep scores will be more on target.
Also, don't do one test after the other. You need to thoroughly review the results of the test, especially how you did by question type, and see where you went wrong before attempting (and therefore wasting) another test. You should also be doing practice questions, weighted a bit more in your weak areas, in between tests.