Background Since 2012, the APHAB is part of the quality agreement for statutory insured patients in hearing aid fitting (HAF). So far, individual results could be interpreted by using percentile curves only, but not for the improvement quotient and the cumulated benefit. The presented study should close this gap. Moreover, it should be clarified if an individual constancy within percentile exists. Methods Using the data of 6861 hearing aid fitted patients from a database, we calculated the benefit by improvement quotient and cumulated benefit for different age-classes and percentile-groups and presented by a heatmap. Individual constancy of percentile would be calculated using Spearman's rank correlation. Results The average benefit was 21.41. The average of the improvement quotient was 41.01. It was significantly higher (44.36 %) in subjects younger than the average (27.26 years ± 11.86) than in the elderly (37.66 %). It decreased in cases of lower APHAB-scores before HAF concerning the percentile-group, ranging from 23.22 % to 52.07 %. Spearman's rank coefficient for the APHAB benefit was 0.285, Cohen's effect size was small. The correlation between the APHAB-score before HAF and the cumulated benefit was 0.582 and the improvement quotient was 0.270. Conclusions An individual constancy within percentile before and after HAF was not detectable. Nevertheless, some relationships of the improvement quotient and the age resp. percentile-groups could be demonstrated. The benefit of HAF was less in older subjects with lower APHAB-scores and best in young subjects with higher APHAB-scores before HAF.