Hi tgbhu5,
Since the GMAT is a Standardized Test - you (and anyone else who takes it) CAN train to score at a higher level. As such, scoring significantly higher on a latter attempt is not in-and-of-itself an "issue" (and since GMAC makes a significant amount of money from those GMATers who pay to take the Exam more than once, it wouldn't make much sense for that organization to dis-incentivize that group from paying to take those additional attempts). All things considered, you should assume that your Official Score is valid and will remain so for 5 years from the date you took your Exam.
GMAT assassins aren't born, they're made,
Rich