Escalador de escaleras-fitness

I’ve been using this app for several weeks. The history might take a couple days to update, no problem. I use a Matrix stairclimber at the gym. The flights on the machine and the app never matches, nor come close. I turn the app on and put the phone in my front shorts pocket. Today, I did 39 flights on the machine but only 22 showed up on the app. I must be doing something wrong. I’m a beginner climber, great exercise.