Dell Studio 1558 with AMD Catalyst Driver 13.4 or onwards in Windows 8 or Windows 8.1

I'm facing following issues since installing AMD Catalyst Driver 13.4 or onwards.

My current OS is Windows 8 Pro, Display driver:  AMD 13-9_mobility_win7_win8_64_dd_ccc_whql.exe

1. If set Backlit brightness to level 2 for example, and after some time display turns off (turn off display after X minute) by itself, or restart the laptop; the Backlit brightness level remains same (level 2) but the actual Luminosity (Intensity of backlit) changes to something else.

2. If I decrease the Backlit brightness (Fn + F4) to level 0 (the minimum level), and if I further press the key combination (Fn + F4) to decrease Backlit brightness, it will change the Backlit brightness, but the Backlit brightness should not be changing because it already reaches to the minimum level.

These issues are not with Windows 7.

Anyone facing these or similar issues??