Division of labor vs division of work Some authors makes the difference between these two terms.

Could somebody explain what is the difference between division of labor and division of work?
One possible useful distinction between the two expressions could be as follows:

1) Division of work
Assume you have to mail 1.000 letters identical in content to different recipients. For each letter, in order to do that you need to a) fold the letter b) put the letter into the envelope c) write the address d) put a stamp e) go out and put it into the mailbox. Then repeat the sequence 1.000 times. "Division of work" would be to, instead of going through the complete sequence for each letter sequentially, a) fold all letters b) put all letters into the envelope, etc. By performing the same task, you gain efficiency in each task ("learning by doing") and also, you minimize the time needed in between each kind of task/work.
Here the focus is on gaining efficiency by grouping tasks.

2) Division of labor
In the same example, division of labor would be not only to perform each task for all letters instead of all task for each letter, but have different people doing each task. This situation focuses on the phenomenon of different people specializing in different professions.

...And I am certain that some authors that use the distinction, use the terms switched -namely, they call "division of labor" 1) above, and "division of work" 2).