The fact that there are line numbers missing would not have an effect, and I did note that the line n10 is missing from bpopup, but since I know that the missing line number makes no difference (unless you're trying to refer to that specific line in a $readini command), I didn't realize it was properly part of your bug report.
However the multiple lines having the same N# reference, I think should be called a bug as the /writeini routine, to my knowledge, should've over-written the previous entries with the newer entry.
Therefore there should not be two or more lines with the same N# reference.
