Thanks Cindy. I realize now that I don't surround my replacement values
with quote marks, even when they're IF operands - perhaps that's
causing problems. E.g., the example above becomes
{ IF Phone = "Phone" "{ IF 701 "" "701-" "" }333-2398" "" }

which then becomes
{ IF Phone = "Phone" "701-333-2398" "" }

which - if Word recognizes the equality - should resolve to
701-333-2398 (which is what happens on all computers but the one)
or otherwise to nothing. Why I'm seeing 333-2398 on that one machine is
still a mystery. I'll post here when I figure it out.