Expired Carts not Expiring

Hey,

I have a lot of carts with a null for meta.modified.  This means the Episerver expiry script will not expire those baskets as it says 

Meta.Modified <  GETDATE() 

am I missing something or is there a bug in the expiry script?  Here is the sql I ran to see the missed baskets

select count(*) from ordergroup left outer join OrderGroup_ShoppingCart on ([OrderGroup_ShoppingCart].ObjectId=OrderGroup.OrderGroupId) where modified is null