GMAT scoring

The differences that you see are due to the way the GMAT calculates and reports scores.

1. The GMAT generates a score at the end of both the quantitative and verbal sections. These scores are on a continuous scale.
2. These scores are mapped onto an internal scale. Let's call these scores "internal scores".
3. These internal scores are combined to arrive at a total (internal) score.
4. All these scores are then converted to the scaled scores that are exposed to the test taker (6 to 51 for quant and verbal, and 200-800 for the total).

The internal scales are slightly more accurate than the ones exposed to you. For example, let's say two people got a Q49 each. Now, a Q49 could indicate a performance level anywhere between 74% and 85% (Q50 is 85%), so it's entirely possible that one of them got a "low" Q49 and the other got a "high" Q49. This is the reason that you don't always see the same total for the same score combinations.