I'd take another practice exam. Those results aren't particularly close. If I had to guess, I'd assume you're closer to the GMAT prep score, since GMAT prep exams seem to be the best indicator of actual results (among the various prep exams floating around the internet). But do I know what you'd score if you took the real exam right now? Nope. But you could tell me you score four 720s in a row... and I still couldn't tell you what you would score on the real exam today.

Best of luck, Ben. If you have any other questions, I would be happy to try answer them for you.

Speaking as a Veritas employee, even I will admit that the GMAT Prep test score is likely more accurate. Any practice exam other than GMAT Prep is simply a guess as to how the GMAT algorithm works, so they are naturally not as accurate.

If I had to guess, I would say that your "true" score at this point is somewhere in between the 700 and the 580. I would interpret your score results as follows:

1. You're capable of scoring 700+, especially with four weeks to go.
2. You need to work on consistency and not getting thrown if something goes wrong. It's certainly possible that you could get two RC passages in a row on the real thing. Test takers who know their stuff "cold" should break 700 on any practice test, GMAT Prep or otherwise.

It sounds like you're moving in the direction - focus on your weak areas and keep up the good work.