Some Greatest Hits collections contain tracks which have been designated as part of a compilation, even though the Artist of each track is the same. (iTunes' "Compilation" is not exactly synonymous with "Collection".) If you maintain a "Compilations" folder, and have set iTunes to "Keep iTunes Music folder organized", these Album folders will appear there and not in their respective Artist folder. Changing each track's Compilation setting to "No" will un-designate them as part of a compilation and allow iTunes to move the Album folder to the appropriate Artist folder.
This script goes through your entire library looking for such tracks and changes their Compilations setting accordingly.
Designated as a Retro Script because iTunes can do this.
OBLIGATORY WARNING! Because this script has been designated as a "Retro Script" there is no guarantee that it will function as described and may even corrupt or destroy data.