There is a never ending battle between those who insist on estimating in story points and business people who say "how many man hours will that be?"
I have also never been involved in an Agile project that does any validating of how accurate the prior estimates were. But Ideal Days could easily be validated by the business.
I am considering Ideal Hours. Day are too large, ideal or not.
How about Ideal Fibonacci Hours?
I'd like to hear what things others have tried, but an leaning away from points...