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Major point releases? You can call them that way, but RH call them minor releases. Major release is RHEL6 or RHEL5.
Then there is minor releases, 5.x and what you call minor releases are in fact micro releases (that's how Red Hat is calling it), little updates with some fixes. Those come to centos quicker than minor releases but not that quicker. CentOS is late about 7 to 15 days with micro releases. It still needs a fair amount of testing to maintain 100% RHEL compatibility.
But don't get me wrong, that is not bad thing. I would hate to see it come out same day as RHEL and then make some problem or even bork my server.