Sounds close to right. A4 2.5tdi's only get low 30's.
Never really understood the point of a V6 TDi, unless you tow chieftan tanks for a living.
On an A4:
1.9TDi 130bhp will deliver 48mpg (more on the motorway)
2.5TDi delivers 32mpg, same as a 1.8T/2.0T
I know it's all about torque (yawn) but I'd have a 2.0T anyday for the same economy. The 1.9TDi struck the right balance between bearably decent performance and economy so makes perfect sense if you do a lot of miles.