Using exiftool with -tagsFromFile

[PabloG]

I have a picture that is modified by an external program and the problem is that the metadata is lost.
So I use exiftool to "restore" the original metadata by calling exiftool -tagsFromFile specifying the original JPG and the modified one.
Problem is that from time to time I see differences in numbers having decimal separator.
For example Max apperture is originally 3, and when I use exiftool -TagsFromFile, the target file has 2.9708....

Is there a way to handle these values properly

Thanks

[Phil Harvey]

I think this is related to FAQ 4.

To help more, I need you to answer these questions:

1. What was the command you used to copy the metdata?

2. What is the output of this command for the original file?:  exiftool -maxaperture -a -G1 -n FILE

- Phil