Tyre sizes, will 235/65r17 fit C6 Allroad?

[Sverige]

I’m confused about tyre sizes for my C6 2007 3.2FSI Allroad! From online sources I see these are the acceptable tyre fitments:

• 225/55R17.
• 245/45R18.
• 245/40R19.
• 245/35R20

But locally to me I see a nice looking set of 235/65r17 winter tyres advertised and I am wondering, will they fit my car? It’s not a size which is in the above list, but surely 245/40r19 has the same outside diameter as 235/65r17? (19x25.4+80= 563mm compared to 17x25.4+130=562mm)

So will 235/65r17 work on this car and if so, why doesn’t it appear in the list of recommended fitments? Is a 65mm high sidewall just too tall for cornering?