I'm not convinced either, but don't know enough about it. Apparently, some oil out of the old turbo may be in the exhaust or catalytic converter, and needs to burn off. I need to give it 3 or 4 weeks to clear itself. I am just repeating what I was told!
There were no codes showing, and they could not get it to smoke on a test drive. Apparently the mechanic who has been working on my car ha 15 years Toyota experience.
I did 400 miles over the weekend, at least 90% on motorway or dual carriageway! I also would have thought that would be enough to clear it.
I think I am going round to my local Toyota dealer for a chat tomorrow.