Reproduced on 4.2.b1

When you select an AudioClip, Unity displays the AudioImporterInspector. In the AudioImporterInspector, the initial maximum value for "Compression (kbps)" is incorrect. It receives the correct value once you click "Apply" or "Revert" though.

Reproduce:
1) Open example project attached to this bug report
2) Select the asset "Assets/airlock_door_close 5.wav"
3) Drag the Compression slider in the AudioImporterInspector to the most right (max value).
=> Notice that it displays "256" at this point.

4) Click "Revert"
5) Drag the Compression slider in the AudioImporterInspector to the most right again.
=> Notice that is displays "240" now, which seems to be the correct value.

Expected behavior:
The Compression slider show display the correct maximum value (240) to begin with.