>Try something like:
>
>USE ABCDEF ALIAS MNO EXCLUSIVE ORDER XYZ
>SELECT * FROM MNO ;
>WHERE Fld1 = Expn1 ;
>INTO CURSOR Temp

Okay, I did with one exception. I added an alias() as another field to retrieve. So the above would be:
SELECT *,alias() FROM MNO WHERE Fld1 = Expn1 INTO CURSOR Temp

The results were that alias() returned ABCDEF because it opened the table again in another work area and was able to use the original alias name. When the same query is done without specifying an alias in the USE, alias() returned B (the second work area).

FWIW, my test numbers jumped around so much with such a small difference (using a 100,000 record table) that I didn't make a determination whether having an order set was particularly bad for performance.