The initial run of a job in SkySync a creates its tracking database (Mpa of the file hierarchies of the source and destination) and the size of that content is the amount of transfer limit used. This hierarchy is used on all subsequent job runs to determine the files that have either changed or have been added to the hierarchy. Newly added or modified files will be appended to the transfer usage from all previous runs since those files will now be under management by SkySync for future job runs.
The following actions can affect your transfer usage: Resetting a job, renaming files or folders, alterations of file time stamps or changing of the file size.
If the tracking database is significantly altered or corrupted a reset of your SkySync job may be required which will in turn necessitate the building of a new tracking database. If you have moved content in the source or destination using an external method from SkySync (for example FTP) then SkySync will have to build a new tracking database. Similarly if you move content that have been synced earlier from one folder to another folder within the same destination location, SkySync will require to rebuild the tracking database.