Erm, not quite sure I'm on the same wavelength. Are you mixing up bit 4 & 7? As far as I can make out 0xF0 is not an allowed combo.
0xE0 = 0b11100000 : CKDIV=1 (disabled), CKOUT=1 (disabled), SUT=10 (65ms startup), CKSEL=0000 (ext. clock)
0xF0 = 0b11110000 : CKDIV=1 (disabled), CKOUT=1 (disabled), SUT=11 (reserved), CKSEL=0000 (ext. clock)