Bonuses
Management probably want to keep the bonus system going because then the sallary and bonus combined are an awesome package, but it is not cast in stone, as it would be were they to just raise the sallary to the combined figures. After 3 years they will probably review the crewing situation which is highly unlikely to be any better (for employers) than it is now and they will have to come up with another insentive or sallary increase to keep people interested. I therefore think it is a fairly safe bet unless we have another SEP 11th or something.