This percentage is wrong (I think) because the "used capacity" of 1 of my local drives (NTFS) is less than the "Fragmented Files". In attached example you will find: "used capacity" = 9.3 GB and "fragmented files" = 9.7 GB.
I think that one of this calculations is not working correctly.
Also, attached you'll find some screenshots and logfile of debug mode (started defraggler with /debug parameter).
Please let me know if you need anything else.