I think that's how the dealer told me it works. For normal driving it's pretty much the same as without. The main benefit comes when parking as it makes the steering quicker to full lock or for getting around in tight multi storey car parks it can help get round the tight bends.
What I was told is a bit hazy now but it was enough to convince me it would be beneficial as my work parking is one of those tight car parks that can be a nightmare so the £375 or whatever it costs would be a small price to pay
