Command Prompt Control

I'm having trouble with the prompt control for a command I am
writing. I have a second and third parameter that I alternately don't
want prompted depending upon the first parameter's value. It works fine
if I actually put a value in the first parameter. But if I leave the
parameter blank, prompt control shows both the second and third parameters
when it should only show the second. These are the prompt control
definitions I have. It seems to me that these cannot both be true at the
same time. Any help?

NOBODY: PMTCTL CTL(MSGID) COND((*NE '*LAST') (*EQ ' ')) +
NBRTRUE(*GT 0) LGLREL(*OR)

LASTHDR: PMTCTL CTL(MSGID) COND((*EQ '*LAST')) NBRTRUE(*EQ 1)


Sincerely,

Dave Clark