yup, that's why when i was doing computer work (for a Fortune 500 Company that will go unnamed) i'd take the time i THOUGHT it would take, double it, then raise it to the next highest time increment...so a job that i thought would take an hour would be quoted as two days since i never knew what i'd run into or how may other rush jobs i'd be rushed into doing while doing the rush job i was rushed into quoting on
come in under time and you are a hero, on time, well you did your job, longer than that, feh, it made no difference they ordered you to do two other rush jobs in the meantime