Thank you for your post!
I am going to move this thread from the FileMaker Community Feedback Space, which is specifically for input on the Community itself, to the Discussions Space where you should receive more views and potentially more advice!
We use a script trigger to get the original data and a scrip trigger to get the new data and then fill a log field in the record.
We fill the field with a modifier name, modifier timestamp and the changer that are made.
[Karina 26-Jun-2016 20:00]
Changed the field [sales price] from $10.00 to 9:50
[Karina 24-Jun-2016 20:00]
Changed the field [sales price] from $12.00 to 10:00
[Karina 24-Jun-2016 19:00]
Changed the field [status] from 0 to 1
Let me know if this is what you need.
If you need help with creating the scripts, I can create a sample file for you