macOS enforces a number of “common sense” restrictions on your use of creation and modification dates for files:
This means that if your file was created yesterday, it cannot possibly have been modified last week (it didn’t exist yet) and if your file is on the hard disk this means it already exists and can thus not be first created tomorrow.
The way in which different versions of macOS enforce these common sense restrictions, however, has changed a few times in the last few years and has lead to some “strange” behavior when you are manually changing these dates with a tool such as A Better Finder Attributes.
When the “Automatically correct inconsistent dates” checkbox is ticked, A Better Finder Attributes will automatically deal with these problems by doing the common sense thing:
If the new creation date of the file is later than the last modification date of the file (i.e. it would now have been created after it was last modified, which makes no sense), A Better Finder Attributes will put the modification date to the new creation date, (i.e. the file will have been created and modified at the same moment, which makes sense).
As a user of these features you need to be aware of the fact that changing one of the two dates (modification or creation date) may also result in a change in the other.
We recommend leaving this feature switched on, but if the checkbox is unticked, the program will ask you to make a choice for each inconsistent file date problem individually.