Lots of questions...
Championships are decided regionally by class and overall. The RACE OF CHAMPIONS is an event where riders from all the regions get to hack it out for a "national championship". Luck, money, whatever, can all play into it.
The season was for the regional championships. ROC is different.
Frank, what you're saying is kind of like how WERA used to do it. I don't know if they do it now. GNF, Grand National Final, is kind of the same thing. Suzuki Cup, Suzuki World Cup, the former Honda Challenge Series, etc.
To me, personally, I believe that a whole season of races really determines a championship performance, rather than one race. But ROC is fun.
This overall championship thing by region is goofy. Everyone should have a reasonable chance for it, but if you have certain bikes, you cannot "compete" because you cannot enter enough classes. Or you don't have the money to race nine classes a weekend, let alone pay for the tires....