Timer On, Timer Off

After a few tries, I finally figured how to use the two timer buttons on aircon remote control. I thought Timer On is to turn on the timer in order for it to countdown to on the aircon whereas Timer Off is to turn of the timer if I don't want it later. But......... I was wrong......

Timer On - turn on the aircon after the duration is set

Timer Off - turn off the aircon after the duration is set

No wonder, when I set the timer on, the aircon never turned off.......