Today I had something strange, I had to climb a tower with in total about 20 meters height difference.
I climbed this tower (spiral staircase) two times and the alitmeter seems to be following it quite good.
When I look at the number of floors climbed it displays 4 whilst my iPhone and Android phone both displayed 12 floors.
For some reason the detection of the number of floors climbed seems to be a bit off, the only thing I can imaging is that the spiral staircase was split into two sections so it is 4 flights of stairs in total but the number of floors is not correct. I don't know what altitude difference Apple uses to determine a floor.