what do Coveralls messages really mean?

Every single pull request I get a message from Coveralls automated
checks that test coverage has decreased:


Coverage decreased (-1.08%) to 78.797% when pulling [Blah] into [Blah]


occasionally, I get a separate message which also tells me coverage has
increased, on the same PR....

For the one I sent just now, it is clear that coverage is completely
neutral... an extra version string was added to two lines so there
cannot be either an increase or decrease in code coverage since the
number of lines remains unchanged.

Note that the actual report shows, as it should, no change:

https://coveralls.io/builds/18935772

should those emails just be ignored, then?