It seems to me that I read (perhaps at the Ross-Tech web site) that the factory repair manual can be trusted to carry all vag-com code interpretation material,whereas the service manual may be deficient in that regard. I don't have time, now, to research. Hope I'm not sending you on a wild goose chase, but there is a destinction that favors the factory repair manual. And, it has to do with completeness of information as relates to use of the vag-com. Please post what you may find.
I presume you are aware that registered Ross-Tech vag-com users get some kind of price break by buying Bentley materials through Ross-Tech.