Phone apps aren't nearly as good as dedicated measurement systems. Think about it: The phone application developer has no way of knowing what quality the microphone or input circuitry is like, so the system cannot be calibrated. Phone measurement apps are gimmicky, at least at this time. One could calibrate the hardware though, so those kinds of apps could potentially become more accurate at some point.
Thank you for the input. I did not think about the microphone's difference between those smartphones because I do not feel like it is an important feature when choosing a phone to buy. I have heard that it is possible to add external microphone to the smartphones, though. I wonder if that will help to solve the problem, given that we can modify the application's settings to match our new tool.