Regarding your pay question, here in France it's random people, you and me, who are election workers (I explained the process in another reply): it's definitely not paid.

And the counting is done in polling stations after the voting process: just more hands and eyes that way.

And because it's that distributed, it's pretty much parallelized as much as you could. Another quality is you'd have to corrupt a fair amount of polling stations to make a substantial difference if you wanted to cheat.

Results are then sent to the next level (usually city hall which aggregates that and then sends that to the next level).