The dealership ended up filling it, but in the process they gave me a "Technical Service Bulletin" which seems to address a problem of the "Refill AdBlue" message show despite adequate level. The solution is to use a diagnostic computer to run a function called "Adapting reducing agent tank adaption values".
I'm about to purchase an A6 3.0 bitdi and I have found out that it is due the an Adblue & Nox sensor update. B8 Forum - 2008 - 2015; Audi A4 - B9 Forum - 2015 Trending Audi Cars. The Audi A4 comes with a tank capacity of 63-litres in petrol variants while in diesel models it offers capacity of 70 litres. Using the DrivePro diagnostic software, Opus IVS’ remote IVS 360 team guides a customer through diagnosing and repairing an Audi A4 with AdBlue warning fault. Recently, a customer requested support on an Audi A4 (2016 – DEUA Euro 6 Engine). They reported an AdBlue warning on the instrument cluster, stating “No engine start in 500 miles . 23 0 408 86 308 121 338 433