The more recent your last vote before the hardfork was, the more your voting power was impacted. This behavior is a one time issue that will resolve itself over the next 5 days. Some accounts even got a negative amount of RC, but this has been solved by a patch.
About why a power up did not have an inmmediate effect in RC I have two theories:
The RC system is in stabilizing process.
Powering up only increases the maximum RC and the regeneration rate, but does not instantly increase the RC amount.
Your experiment has created an enormous bounty for this post.
Yea this is fixed now, but we had to shut down the service until we have rc again