VAG diesels do seem to use a bit of oil apparently by design as others have said. The Mini we used to have used none at all in almost 3 years. Perhaps it's the fuel contamination from the DPF process thinning the oil and it passing into the combustion process, I think BMW use a chemical process on the mini?
Above all in my experience it would seem granny driving and softly softly in the first few thousand miles on a diesel will give you increased oil usage.
I'd disagree that use of some oil by design seems to be the norm. I'm on my 7th TDI from new and my Dad is on my 4th. Save for 1 of those 11 cars, we've never had to top up between services.
I'd agree that a very soft run in is probably the most common culprit for "acceptable" oil use. My 1 problem TDI (as far as oil use goes spent it's first 800 miles sat on the motorway doing 75mph in 6th. It used a litre in the first 350 miles after i'd driven it from Burnley (it was picked up from there - broker car) down to Southampton (where my parents now live) and across the ferry to LeHavre where it immediately asked for a top up. When I drove it back up to Newcastle, it needed a top up, and was thirsty for oil (crap mpg too) the whole time I had it.
I'll never run a car in like that again, varied driving around the doors for a month before I do a 100+ mile journey in the next one.
They wouldn't give you the top up oil if they didn't expect it to be used. You don't get them with petrol cars IME. My Audi handbook states consumption may be higher in the first 5000km. They know they use oil, give you something to temper the initial high usage then you're on your own. Granny it at your peril
Given your posts on here you seem to drive similarly to me - our GTD hasn't used any so far as it was given the firm but fair "run in"
My own A4 was terrible when I got it with 20k on the clock as it had been driven lazily. Once I'd broken it in properly the consumption has dropped to nothing at 70k, I don't need to top up between services. Similar to your experience with the early motorway driving on previous cars.
As with everything your mileage may vary. All engines are different.