Just a note mar77a, just because a given file has a number of lines %4 = 0 doesn't mean that that file doesn't have that problem, if it happens a multiple of 4 times.
A better way to check a file is to parse it and see which lines you can find "--- <date> <time>" on, and if it doesn't happen every 4 lines then you have a problem. I bet if you checked every file this way, you would find more problems.