Odd listings for Aston DBS Volante

[Beefmeister]

Small issue I know, but when searching for Aston Martin and 'DBS Volante' in the keywords box, I get 20 results:

http://www.pistonheads.com/classifieds?Category=us...

Whereas when you go to DBS, then select Convertible it only gives 4 results:

http://www.pistonheads.com/classifieds?CarTypeFF=C...

Wassatabout?