negative tag vs affirmative tag

[Winwin2011]

I read the following sentences from English Grammar Today-Cambridge. The authors say "The tag may be affirmative or negative, depending on the type of tag:

1. You work with Peter, don't you? (affirmative main verb, negative tag)
2. You live near Harkness, do you? (affirmative main verb, affirmative tag)

In the above sentences, they both use affirmative main verbs. However, sentence 1 uses a negative tag but sentence 2 uses an affirmative tag. Is there any difference between them?

Thanks.

[Route21]

1. You work with Peter, don't you? (affirmative main verb, negative tag)
2. You live near Harkness, do you? (affirmative main verb, affirmative tag).

As an NES but not a teacher, my reading of the difference would be:

1. This could suggest that you have already heard that they worked with Peter and are looking for confirmation that they still do, say to pass on a message etc.
2. This could suggest that you were not previously aware that they lived near X as you thought they lived near, say, York.

Others may have different ideas.
Regards
R21