Sorry to burst your bubble, but you are creating false readings and you are putting stress on the unit.
There are 4 chips on each board and 3 x boards, total of 12 chips, the sensor is on the last chip to the rear bottom of each board, the other 3 chips on the board are at the front near the fan, if you reverse the fan the sensored chip is getting cold air first and the other 3 chips on the board are getting hotter air, also the senor pcb is getting fresh air first, not good scenario for the 3 unsensord chips which is now hotter than the sensored chip and the fan is not activating to their real temps.
Normally they are always cooler than the sensored chip and have no need to be monitored.
this makes perfect sense if the hardware architecture was built like this. in this case, with the reversed airflow, the lower temp reading is fooling the control board to slow down the fan therefore cooling the 3 other chips less than required so for all we know, the 4th chip (with the sensor) is fine while the other 3 is roasting away...