At least they told you how you stand before you entered both classes. If they would have told you "sure, no problem" then counted you out when you couldn't make it to the lanes in time then that would be wrong. I would think if you head to the lanes first call for the class they run first then you should have plenty of time to fuel up before they run the second class. The pace would get quicker as eliminations progress if you manage to stay in both classes. Basically they are telling you if you think you can keep up feel free to enter both.