you must again take into acount that there are other unknown (BIOS?) processes which might write to the memory of the embedded controller and around 90°C I found this effect, too:
[07.09.2007 14:53:18] Current Config:
[07.09.2007 14:53:18] Active= 2, Cycle= 5, FanBeep= 0 0, MaxReadErrors= 10
[07.09.2007 14:53:18] IconLevels= 75 85 90, IgnoreSensors=
[07.09.2007 14:53:18] Log2File= 1, Log2csv= 1, ShowAll= 0
[07.09.2007 14:53:18] Levels= 70°C -> 0, 90°C -> 0x80
[07.09.2007 14:53:18] SensorOffset1-12= 0 0 0 0 0 0 0 0 0 0 0 0 °C
[07.09.2007 14:53:19] Change Mode from BIOS->Smart, recalculate fan speed
[07.09.2007 14:53:19] Fan: 0x80 / Switch: 38°C (32; 38; 26; 37; 24; 0; 21; 0; 0; 0; 0; 0; )
[07.09.2007 14:53:19] Smart: Set fan control to 0x00, Result: OK
[07.09.2007 15:02:37] Fan: 0x00 / Switch: 90°C (90; 49; 34; 54; 28; 0; 22; 0; 0; 0; 0; 0; )
[07.09.2007 15:02:37] Smart: Set fan control to 0x80, Result: OK
[07.09.2007 15:02:42] Fan: 0x80 / Switch: 86°C (86; 49; 34; 54; 29; 0; 22; 0; 0; 0; 0; 0; )
[07.09.2007 15:02:42] Smart: Set fan control to 0x00, Result: OK
[07.09.2007 15:03:47] Fan: 0x00 / Switch: 90°C (90; 50; 35; 55; 29; 0; 23; 0; 0; 0; 0; 0; )
[07.09.2007 15:03:47] Smart: Set fan control to 0x80, Result: OK
[07.09.2007 15:03:49] Fan: 0x80 / Switch: 88°C (88; 50; 35; 55; 29; 0; 23; 0; 0; 0; 0; 0; )
[07.09.2007 15:03:49] Smart: Set fan control to 0x00, Result: OK
[07.09.2007 15:04:00] Change Mode from Smart->BIOS, setting fan speed
[07.09.2007 15:04:00] Fan: 0x00 / Switch: 86°C (86; 50; 35; 55; 29; 0; 23; 0; 0; 0; 0; 0; )
[07.09.2007 15:04:00] BIOS: Set fan control to 0x80, Result: OK
->[07.09.2007 15:05:51] Change Mode from BIOS->Manual, setting fan speed
->[07.09.2007 15:05:51] Fan: 0x80 / Switch: 62°C (62; 49; 34; 52; 30; 0; 23; 0; 0; 0; 0; 0; )
->[07.09.2007 15:05:51] Manual: Set fan control to 0x00, Result: OK
->[07.09.2007 15:10:08] Fan: 0x01 / Switch: 90°C (90; 52; 37; 56; 31; 0; 23; 0; 0; 0; 0; 0; )
->[07.09.2007 15:10:08] Manual: Set fan control to 0x00, Result: OK
[07.09.2007 15:10:25] Change Mode from Manual->BIOS, setting fan speed
[07.09.2007 15:10:25] Fan: 0x00 / Switch: 87°C (87; 52; 37; 57; 31; 0; 23; 0; 0; 0; 0; 0; )
[07.09.2007 15:10:25] BIOS: Set fan control to 0x80, Result: OK
[07.09.2007 15:13:39] Change Mode from BIOS->Manual, setting fan speed
[07.09.2007 15:13:39] Fan: 0x80 / Switch: 57°C (57; 49; 33; 51; 32; 0; 24; 0; 0; 0; 0; 0; )
[07.09.2007 15:13:39] Manual: Set fan control to 0x40, Result: OK
[07.09.2007 15:14:50] Fan: 0x40 / Switch: 52°C (52; 48; 32; 49; 31; 0; 24; 0; 0; 0; 0; 0; )
[07.09.2007 15:14:50] On close: Set fan control to 0x80, Result: OK
[07.09.2007 15:14:50] Exiting ProcessDialog
15:05:51 tpfc writes 00 to the fan control byte and 5 minutes later at 90°C
it finds 01 !!! Then it writes back 00... I think there are borders of the use of tpfc
