Interesting. As someone who spends half her life automating list numbering, I have to say I do no not trust the paste and format options one bit - I have seen too many anomalies, notably the anomaly that brings in corrupt list templates and unwanted styles from the source document. I wrote myself a little "list template snooper" to keep an eye on what happens with the paste, and it doesn't always reveal a pretty picture.

IF the styles in the source and destination document are identical, a straight forward formatted pasted ought to produce the desired result. That happens in a "perfect world".

Having said that, I would also mention that I have found that Word 2010, unlike Word 2003, even if source and destination document have identical styles, if the documents originated from different template containers, restarts will often not survive the paste. The cure I find for that is to ensure that, either, both documents originated from the same container (impossible to control), and the numbering styles are linked to the list template via a list style. With both of those conditions in play, I find pasting restarts is more reliable than any version of word ever, even if the styles are not identical among the two documents.

If this is something you do frequently, you might to consider changing the multilevel list to avoid the restarts altogether. If there is something consistent between the lists (a heading or a body text paragraph), that should be pretty easy to do, e.g, edit the MLL to male level 1 un-numbered, and set level 2 to restart after higher level, like this:

Level 1 style, un-numbered
1. level 2 style and paragraph, restart after higher level
2 Level 2 para

Level 1 style, un-numbered
1. level 2
2. level 2

Hopefully this gives you some ideas.