In NTFS there is a record in the Master File Table for every file created. When a file is deleted its record is flagged as deleted and is available for reuse by future file allocation. When Recuva runs a normal scan it reads all those deleted records in the MFT. That is where the count of 488896 comes from.
Although the deleted file records may point to the file data clusters, those clusters may have been overwritten or otherwise changed, so that the contents are of no use. It depends on how the files were deleted and what activity has taken place on your pc.
The number will change as the pc is used but it can't be reduced artificially. If Recuva said 0 records found it wouldn't be much good as a recovery tool.