Few correction.
What you refer to hash in your article, is not hash of the block header, It is proofHash, calculated by hashing Kernel. If the hash would be hash of header, we would have a PoW coin. Components of the kernel, read Stake V8 wiki article.
Second, are you sure that diff if maxTarget/target, I did not know how the difficulty value was calculated until now.
Your formula for calculating the amount of coins staking will be very useful in next development, especially to calm down @erkan. Please post your formula to Github, so it is not lost!
Thank you for your research, you did a great job!