$e1days = $e1days + $e1diff_day; # add difference in days to days
to $e1days = $e1days - $e1diff_day; # add difference in days to days
Edited to post that it only works in the existing month. If someone comes up with the code for a countup counter, please let me know. I removed my code, as it wasn't necessary, it doesn't work correctly. Back to the drawing board!