The effect of approach mode (ascending versus descending, A-D) on comfortable loudness was determined for a 1000 Hz pure tone using Bekesy audiometry. Two groups (experimental and control) of 10 normal-hearing young adult subjects measured their most comfortable loudness (MCL) levels pre-and post-treatment. The experimental group received a treatment of a listening exposure to a 70 dB intensity range before the test. The results demonstrated a statistically significant change of the A-D gap in the experimental group while the A-D gap for the control group remained essentially unchanged. It is proposed that MCL is underestimated in the ascending approach and overestimated on the descending testing, which results in the A-D gap. In addition, the results demonstrate the importance of the procedures used in research and clinic of the MCL.