Erel
The effect of additional timezone is only in the device, while in the emulator it seems not to care what is the timeshift and provides the correct answer without any subtractions.
In the device the addition of the time shift does not make sense because the value of the ticks should be exactly what I input by ticksperhour or any other parameter. by subtracting the start value of the ticks (=0) you should not change anything because you are subtracting zero, but actually you subtract zero+time shift added by the OS, so you get the required result.
I think it worth a note in the documentation because it is not something you would expect, especially the difference between the emulator and the device (or is it only in my A81E device?)