When Time Machine says "I will delete the oldest files first" does it mean this literally. Here is a theoretical example.

Source Drive: 300 GB, consisting of 1 280 GB file and a 1 GB file.

Backup Drive: 300 GB

The initial backup will backup both files, using 281 GB. If I modify the 1 GB file 21 times, what will Time machine do when I run out of room on the backup drive; Delete the original 280 GB because it is the oldest file or delete the oldest version of the file I have modified 21 times. I hope it would delete the oldest version of the file I have modified 21 times, but I want to be sure.

Thanks, Joel Budgor