I'm not sure what you're asking. Timer0 counts up (increments) by one every instruction cycle (without prescaler). It starts at from $00 and counts up to $ff. The next time it increments it rolls over to $00, triggering the interrupt, and keeps counting.
So you're polling the timer looking for it to hit 16 ($10)? I'm no expert, but I'd think that you're unlikely to "be there at the right time" very often. Wouldn't it make more sense to preload the timer with 241 ($f1) and 16 cycles later (I added two for the two-cycle inhibit after writing to TMR0) you get an interrupt. (I might be off by one...) That way you're sure not to miss it.
I'm not sure what you're asking. Timer0 counts up (increments) by one every instruction cycle (without prescaler). It starts at from $00 and counts up to $ff. The next time it increments it rolls over to $00, triggering the interrupt, and keeps counting.