I agree with David's comments about the primary key. You really need to change it.
The slow update is mainly due to the NOT DELETED() in the index. Using NOT DELETED() is a huge performance killer with TABLEUPDATE(). Since your primary key is made up of user entered data you must have the NOT DELETED() filter. This in another reason to use an application-generated, meaningless, integer field for a primary key.
>13 fields, length 105.
>
>TRying to update 7000 records.