I bought a site and the person says that the domain is registered at ipowerweb and it will take 14-21 days to transfer it to me. I have never heard of a waiting period
I have a website hosted by homestead and they say transfers can take up to 2 weeks. A diff. website I had hosted by citymax takes up to 4 days.
I heard 2 to 3 days max. Donno why that is so long. But I guess it depends on the service you are taking.
Why transfer it at all? If you create an account at their registrar, they can usually 'push' the domain onto your account for free, and you can go in and chang the nameservers and contact information immediatly. It's only when the domain is being transferred from one registrar to another that there's usually a waiting period.