>In this WHERE clause, I have parentheses:
>
>

>WHERE Client.NoProvince=@NoProvince AND
> NOT (Client.Status<@Status AND Client.NoStatus=@NoStatus) AND
> NOT (Client.Status<@Status2 AND Client.NoStatus=@NoStatus2) AND
> NOT (Client.Status<@Status3 AND Client.NoStatus=@NoStatus3) AND
> NOT (Client.Status<@Status4 AND Client.NoStatus=@NoStatus4) AND
> Client.NoCountry IN (1,2,3,4,5,6,7) AND
> Client.FirstName LIKE @LXList1Clm_No
>

>
>Would there be a way to avoid the parentheses? I see the execution is much smarter without those.

if "NOT" it is the culprit

 WHERE Client.NoProvince=@NoProvince AND
  (Client.Status>=@Status   OR Client.NoStatus<>@NoStatus)  AND
  (Client.Status>=@Status2  OR Client.NoStatus<>@NoStatus2) AND
  (Client.Status>=@Status3  OR Client.NoStatus<>@NoStatus3) AND
  (Client.Status>=@Status4  OR Client.NoStatus<>@NoStatus4) AND
 Client.NoCountry IN (1,2,3,4,5,6,7) AND
 Client.FirstName LIKE @LXList1Clm_No

avoid the parentheses not possible without a fully expansion of the AND operator