Without reading what Maslow had to say on the topic I would guess that service to others is a higher, more difficult aim than "self-actualization." Both are worthy pursuits, and I think the most effective service comes after we have at least dabbled in the first five levels.
The irony is that I think our natural selfishness causes us to avoid self-sacrificial service, no matter how often folks who have done let us in on the secret: nothing brings you more gratification, feel-good hormones and happiness than giving of yourself for another being or cause. It is actually very selfish! Maybe true enlightenment eliminates that pride in altruism, but at least in part it serves a purpose as motivation. If only we hungered for service the way we hunger for food ... sounds familiar.