If your power loss is only a few hours, it shouldn't affect your multiplier significantly.
There is a mistake in the whitepaper. It is possible to run more than one staking wallet for the same key. I did not realize at the time of writing the whitepaper that your own wallet would reject your 0 reward mints, meaning that you would never be subject to a penalty for "cheating" on the target interval of 2 minutes. There is one exception, which is the "experimental" build I put out during the midst of the biggest problems with Turbo Stake. One person was a victim of not updating and then staking two wallets. Their multiplier went from 18 to 0 and stayed that way 2 days. They had had plenty of time to update from the experimental build, but we will cover them under the Turbo Stake Warranty anyway.
As long as you are running the latest client, you won't have to worry about this problem. The latest wallets will not allow you to get penalized for staking two blocks within the target interval.
History repeats itself--multipiers reset, dev keeps on staking at the highest percentage---