Something that easy turned out to be pretty hardcore
Take the file modification time in seconds and subtract the start time of the find program. This is the number of seconds in the past that the file was modified. Now divide by 86400 and discard any remainder. This is the number of days ago (as computed by the find command) that the file was modified. So the result you see is the expected result. You want:
-mtime +0
Solution found here www.unix.com/…/..problem-find