The difference is that lawyers typically charge by the hour. Software is not sold based on how long it took to create.
So, if a lawyer bills $1000 for "10 seconds of work", it smells fraudulent.
If $1000 was a flat rate, then it's similar to software: you're purchasing some IP and passing off legal liability to the lawyer. How long the lawyer spent on it doesn't matter.
Why would it be fraudulent if the fee agreement disclosed it?
In the lawyer's case one might argue that it's just a time quantization inaccuracy. There's no smaller unit of time than an hour for them.
One can argue that there should be, but billing in 10 second increments might also be a bit much to ask.
One would hope that they would at least aggregate multiple smaller-than-resolution time blocks into one before billing though. (Five documents over the course of a week ends up costing the same)