Data field compute() may not be called a 1Hz?

I haven't noticed any such problems.

But I once used “variable ++;” in onUpdate(dc), and with every update, the variable was incremented by 5. After I moved the code to compute(), it behaved normally—it was incremented by 1 with every update.

Yes, on most devices when you start an activity and you have a native timer field on the screen you'll see that for the first 10 seconds it displays "1/100th" of second accuracy. On some devices during this time the compute method is also called moire frequently (though not 100 and not even 10 times per second IMHO)

Though strange, because I'd think that during the first seconds the onUpdate is called many times per second, not the compute.