Yes that's what it means.

You also have to take in account that migrated/chained rows can occupy some extract blocks.

Also if you have LONG/LOB/BLOB objects in your table, those can take a lot of extra blocks you don't see using this query.

But if no chained/migrated rows, or (B)LOB's, it's just a fact that the table was created with an initial extent that was too big.

You can do a "move table" ( since you in 8.1.6 ) and specify new storage parameters.

Hope this helps
Gert