When one takes a file from a software and uses it somewhere else, without change. Then the same file has different copyright years. To me that would be to confusing. That is why I can not believe the following statement.
I am unsure what the confusion is about... When the second project updates something, it is the whole work that the copyright years apply to, not just a specific file, so the dates for all files should be updated in that second project. Since file was originally written for a different project, it is logical that it will have different copyright dates -- it cannot possibly have the same dates as the second project (unless, ofcourse, both projects have been updated in the exact same years). The original project from where you copied the file might not have been updated, so no change in copyright dates for that particular copy of that file.
