You'll be surprised, but THERE IS NO any difference between SEEK and SEEK(). Though, I'm very proud that you
are using Seek(). So, if you like Seek() more :

CREATE CURSOR zzz (dd n(5))
FOR i=1 TO 10
INSERT INTO zzz (dd) VALUES (i)
NEXT
INDEX on dd TO zzzi
? SEEK(2,'zzz','zzzi')
? SEEK('2 anything else','zzz','zzzi')
? SEEK('2.0','zzz','zzzi')
USE IN zzz
RETURN

Is it better ?