I've just come up with the answer as to why that could potentially have been allowed by the FAA;
The letter of the law says the limitations of the underlying certificate.
So the requirement to have a "type-rating" for a SE Turbo prop is not a limitation listed on the license. It gets a little convoluted but it may be the UK CAA would not allow you to fly a N-reg PA-46 in UK Airspace while the FAA would be perfectly happy to let you fly it in US Airspace as it is not a limitation listed on the license, rather a regulatory requirement.
Make sense?
In any case you want these opinions in writing as another FAA Inspector from another office may not be as aware.
Wouldn't be the first time.