I am not sure this is actually clearer. If you have 0.12.0.0.0.R for RCs then the release version has to be greater (in IPS' terms) so it has to be 0.12.0.0.1.0. But, if we need to do a respin (0.12.1 in OpenGrok versioning scheme) this would have to become 0.12.0.0.2.0 which is confusing. And, we are not even talking about stable branch of 0.12 yet ! :-)

Or, the release version could be 0.12.0.0.0.R+1 where R is the last RC number.