Yes that is the issue I tend to have with dealer servicing, it is okay getting a special price on VAG service parts, but when that means you get ripped off with the supply of oil -- !!
What they make you think - "oil comes in one litre bottles"
What they buy the oil in - bulk delivery of maybe 200 litres loaded into their holding tank.
That means that the buying in unit price of one litre price, after adding on a reasonable ammount for profit and disposal of the old oil (or do they sell it on for re-refining?) should be maybe for example £3.50 per litre, actual price they sell it for maybe £18.50 per litre.
Now there is a thing called mark-up and there is a thing called daylight robbery - hum, which one applies here?