Mach.h problem

Hi

I am using mach.h to count memory usage of my iPhone application

I am just visualizing a counted value via UILabel on the top.

The point I do not understand is the following:

At the simulator allocated memory is released perfectly (value is growing up and at proper moment is falling down), but on real device it is not ! I run the same code on the device and memory usage value is growing up without falling down !

As a result on real device my application throws memory warrning in some minutes (((.
On simulator application is stable


Why is it so ? What's wrong ?

Thanks