It's doing exactly what you tell it to do.
 

There's the query as you defined it above...
 

And there's the access-accept with a reply attribute of Profile := "Slip".  In your database you clearly have a column titled 'Profile' in radius_auth with value of "Slip" for the row for the username "aseibert@evenlink.com"

To get what you want, you would need a column titled "Slipstream-Auth" with a value of "True" for the row for the username "aseibert@evenlink.com".

But all this is actually a bit horkie.  It makes little sense to have to add a column everytime you want a random check/reply attribute.  It's bad practice and going to be terribly inefficient by any database backend.

Why is it that you don't want to follow the provided schema (in 2.x raddb/sql/mysql/) and predefined queries?