Those are among the standard ratings for such components. It is not "abnormal" for the rating of the breaker to be higher than the rating of the panel. This particular rating only has to do with the ability of the component to withstand a short circuit, without something really bad happening (i.e., explosion, flying molten copper, etc.). So what matters is whether the component is rated for the amount of fault current that can be imposed by the distribution system. I think that most applications of 120/240 volt power in dwelling units would have a fault current less than 10,000 amps. In such cases, the equipment you describe would be fine.
Charles E. Beck, P.E., Seattle
Comments based on 2008 NEC unless otherwise noted.