First of all, if you're scoring that high I sure hope you know that 750 is a great score. 99% about. If you score a Q50 V50 on the real test, that's most likely an 800 (perfect score)....
You are doing excellent it both sections. The best estimate of your score though, is going to be from the GMATprep software on
www.mba.com. The Kaplan score of Q50 V50 only resulting ina 750 is strange to me, so I'd recommend you try one of these tests. Download this software, take a practice test. This is an official practice test from the creators of the actual GMAT tests (there are 2 of them). This should give you a great estimate of your actual score with breakdowns in both sections. It will also show you what percentile each score is so you can know how you did compared to everyone else taking the test. At this point, it looks like you have the ability to hit the 99% in all areas, so that should be your goal.
Congrats, and best of luck!