Hello, dchan. There is not a conversion guide like the one you are looking for. Your score calculations are a bit more complicated than that. Total score is based on raw performance on both the Verbal and Quantitative sections. A range of raw scores will map onto a single scaled score, but since the Total score is based on the raw performance, greater differentiation is possible, meaning the same Quant and Verbal scores can map to different Total scores. It is much like rounding error. Consider scaled scores of 40 for Quant and 35 for Verbal. Say, on the first test, the 'unrounded' scores were actually 39.51 and 34.51, and on the second test the 'unrounded' scores were 40.49 and 35.49. The difference is only apparent when the scores are combined (sum of 74.02 compared to 75.98). In practice, Total scores up to about 30-40 points apart are considered very similar and should be interpreted as nearly equivalent.

I hope that makes sense.